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1Sharda University Greater Noida, Uttar Pradesh 201310, India
2Jamia Millia Islamia, University, New Delhi-110025, India
Guava (Psidium guajava L.) is a highly valuable plant for ethnomedicine, which has been massively accepted and utilized in the regions of Asia, Africa and South America for the cure of diarrhea, diabetes, infections, inflammatory diseases, wounds, and metabolic disorders. The utilization of guava leaves is very effective given that their phytochemical composition is abundantly endowed with flavonoids (quercetin, kaempferol), phenolic acids, tannins, terpenes, alkaloids, essential oils, minerals, and vitamins, which, when used together, lead to potent antioxidant, antimicrobial, anti-inflammatory, antidiabetic, anticancer, and hair growth–promoting effects. The current paper is a review of the aspects of relative importance, phytochemical variability, pharmacological properties, analytical characterization, and the influence of genetic and environmental factors on phytochemical composition. The use of advanced analytical tools such as HPLC, LC-MS, GC-MS, UPLC-QTOF-MS, and NMR account for the precise identification and standardization of bioactive constituents supplemented by strong validation parameters compatible with ICH Q2(R1), AOAC, and WHO guidelines. The overall extraction effectiveness is modern green technology-wise made possible by the methods such as ultrasound-assisted, microwave-assisted, enzyme-assisted, and supercritical fluid extraction. Hence, the detailed phytopharmacological profile of guava leaves opens up possibilities for them to be a sustainable, biocompatible source of natural therapeutic agents for pharmaceutical, nutraceutical, and cosmeceutical applications.
Guava (Psidium Guajava L.) is a tropical evergreen shrub of the Myrtaceae family and is spread in a diverse range of regions in Asia, Africa, and South America. A highly nutritious, medicinal, and economically valuable plant, guava is not only recognized as a fruit crop but also as a major one of the bioactive compounds' sources (Dube et al., 2021; M. Kumar et al., 2021). Accordingly, guava has been a primary source of various healthcare treatments in the indigenous systems of medicine (Auyrveda, Unani, and different folk practices) such as diarrhea, diabetes, cough, inflammation, wounds, and infections (Das & Goswami, 2019; Shaheena et al., 2019). Guava parts, especially leaves, have been traditionally used for common ailments since its therapeutic properties are diverse and they are easily available (Altemimi et al., 2017; Sampath Kumar et al., 2021). Guava leaves are an ethnomedicinal resource that has been recognized by many cultures worldwide. In Indonesia, they are used for the treatment of diarrhea and gastroenteritis. Traditional uses are currently backed by pharmacological studies that reveal the same antioxidant, antibacterial, and anti-inflammatory effects that are to the phytochemical constituents of the leaf (Gutiérrez-Grijalva et al., 2018; Shaheena et al., 2019). P. guajava phytochemicalsurvey reveals that it is a rich source of various kinds of metabolites such as flavonoids, tannins, terpenoids, alkaloids, and saponins. Being the major one, quercetin is very instrumental as a strong antioxidant and reduce the production of inflammatory mediators (Denny et al., 2013; Omcl0205_0270, n.d.). The health-supporting antioxidant attributes of the polyphenolic constituents present in the leaves can greatly alleviate the oxidative problems linked with chronic illnesses of a nature like diabetes, cardiovascular diseases, and cancer (Mohapatra et al., 2024; Vaibhavi et al., 2024). The latest research results also reveal that the leaves have the potential to regulate androgen activity and stimulate hair growth (Madaan et al., 2018). Guava leaves are a renewable, biodegradable, and biocompatible source of multifunctional bioactives. The addition of guava leaf extracts to food coatings, personal-care products, and pharmaceutical preparations provides antimicrobial protection and aligns with the “green” and “clean-label” movement (Sanker et al., 2024; Thanh Phong et al., 2025).
1.1 History of Psidium guajava
Psidium guajava L.'s past can be traced back to the time before the Columbian era when the native people of Central and South America, mainly Peru and Mexico, first domesticated the plant. Archaeobotanical evidence indicates that guava was planted as long ago as 2500 BCE and was not only eaten but also used in healing and rituals. Its spread in the world to tropical and subtropical areas is due to Spanish and Portuguese navigators in the 16th century who took it to India, Southeast Asia, and Africa. Guava in India was termed the “poor man’s apple” as it was loaded with nutrients and cheap, and it got prominent place in Ayurvedic and Unani medicine to be the cure of digestive and metabolic disorders (Das & Goswami, 2019). Traditional healers administered guava leaves and bark extracts to heal diarrhea, dysentery, wounds, and inflammation (Shaheena et al., 2019). Guava, by 19-20 centuries, became a major horticultural and medicinal crop in Asia and Africa, with the scientific exploration revealing the bioactive compounds like flavonoids, tannins, and triterpenoids (Denny et al., 2013).
AIM AND OBJECTIVES
The primary objective is to provide a complete understanding of Psidium guajava L. leaf bioactives by integrating ethnomedicinal relevance, phytochemical composition, and pharmacological importance (Vaibhavi et al., 2024).
OBJECTIVES:
1.3 Phytopharmacological Effects of Guava Leaves
Extensive research on guava leaves reveals to us their various pharmacological and therapeutic attributes. Guava leaves become the source of their antioxidant power through flavonoids and phenols. These substances capture the radicals and recover the user's own defense. The anti-inflammatory features of guava leaves come from the impact of these natural constituents on the cyclooxygenase and lipoxygenase pathways. As the result, prostaglandin and leukotriene synthesis decreases. The antimicrobial capacity of guava leaves is the best illustration of the relationship between the bacterial membrane rupture and enzyme activity inhibition in bacteria like Staphylococcus aureus, Escherichia coli, and Candida albicans (Laily et al., 2015; Ruksiriwanich et al., 2022). Besides that, the herbal drug also delivers very strong antidiabetic effects by means of inhibition of α-glucosidase and α-amylase enzymes, which leads to a decrease in postprandial hyperglycemia. The herbal extracts have also been revealed to exhibit anticancer effects on breast, prostate, and liver cancer through apoptosis, cell proliferation, and signaling cascades changes mechanisms. Furthermore, guava leaf components are capable of immune system modulation, liver, and heart protection as well (Pawar et al., 2024; Sanker et al., 2024).
Phytochemicals in guava leaves that make them highly effective for treatment. The primary groups are flavonoids, phenolic acids, tannins, terpenoids, alkaloids, proteins, essential oils, and essential minerals/vitamins.
Table 1. Composition of Psidium guajava Leaves in terms of Phytochemicals.
|
Category |
Key Compounds |
Main Activities |
Important Findings |
References |
|
Flavonoids |
Quercetin, kaempferol, guaijaverin, rutin |
Antioxidant, anti-inflammatory, antimicrobial |
Major bioactives; levels 29.66–92.38 mg QE/g DW |
(Díaz-de-Cerio et al., 2023; Xu et al., 2020)
|
|
Phenolic Compounds |
p-Coumaric, caffeic, ferulic, sinapic acids |
Antioxidant, antidiabetic, antimicrobial |
Higher in leaves; confirmed by HPLC–MS/MS |
(Ashraf et al., 2016; Chiari-Andréo et al., 2017; Jayachandran Nair et al., 2017) |
|
Tannins |
Hydrolyzable & condensed tannins |
Antioxidant, antibacterial, enzyme inhibition |
Condensed tannins ~17.79 mg TAE/g DW |
(Chiari-Andréo et al., 2017; Farag et al., 2020; Konczak & Zhang, 2004) |
|
Terpenes & Terpenoids |
Caryophyllene, nerolidol, limonene; triterpenes (ursolic, oleanolic, betulinic acids) |
Anti-inflammatory, anticancer, antidiabetic |
Terpenoids ~71.65% of essential oil; 50 volatiles detected by GC–MS |
(Arain et al., 2019; Ashraf et al., 2016; Lima et al., 2015) |
|
Alkaloids |
Pyrrolidine, piperidine, indole, quinoline derivatives |
Antimicrobial, pharmacological activity |
High content (219.06 mg/g DW); ethanol best solvent |
(Chandran et al., 2020; George, 2021; Yumita et al., 2023)
|
|
Proteins |
Essential amino acids |
Nutritional, metabolic functions |
~9.73% protein; good plant-based nutritional source |
(Jassal & Kaushal, 2019; Zaminur Rahman et al., 2013) |
|
Essential Oils |
β-Caryophyllene, α-pinene, 1,8-cineole, limonene |
Antioxidant, antimicrobial, anti-inflammatory |
50–64 volatile compounds; sesquiterpenes dominant |
(Lee et al., 2012; Soliman et al., 2016) |
|
Minerals & Vitamins |
Ca, K, Mg, Fe, Na, Mn, B, Vit C, Vit B |
Bone health, immunity, metabolism |
High mineral content; Vit C ~103 mg/100 g DW |
(Adrian et al., 2015)
|
Guava leaf is a rich source of flavonoids such as quercetin and kaempferol which are the main contributors of antioxidant, anti-inflammatory, and antimicrobial effects. Phenolic acids like caffeic and ferulic acids help in antioxidant and antidiabetic activity. Terpenes/terpenoids such as caryophyllene, nerolidol, and limonene are anti-inflammatory, anticancer, and metabolic-regulating agents, while triterpenes like ursolic and oleanolic acid exhibit potent antidiabetic and anticancer effects. Alkaloids are the source of additional antimicrobial activity. Besides these, essential oils, plant proteins, minerals, and vitamins further enhance the leaves’ nutritional and therapeutic value.
Analytical characterization is basically the initial move in figuring out the chemical makeup, therapeutic potential and the quality of P. guajava leaves. Compounds identification, quantification and validation are made possible by the use of advanced instruments such as HPLC, LC–MS, GC–MS, and UPLC–QTOF–MS. HPLC is the one that offers very accurate quantification, LC–MS and UPLC–QTOF–MS give more pieces of evidence for the structural and metabolomic profiles, while GC–MS is used for the identification of volatile components. NMR spectroscopy is there to provide further support during structural confirmation. Altogether, these methods make it possible to perform the complete chemical fingerprinting which is a very important factor in reproducibility and standardization of guava-derived pharmaceuticals and nutraceuticals (Emam et al., 2025; Huynh et al., 2025a).
3.2 Analytical Methods
3.2.1 High-Performance Liquid Chromatography (HPLC)
HPLC is the most common method to determine the amount of phenolic and flavonoid compounds in guava leaves. To detect the compounds, UV or DAD detectors are used which are based on the compounds' polarity and retention time. HPLC–MS/MS is used to quantify the major phenolics such as gallic acid, ellagic acid, catechin, quercetin, and kaempferol. The technique is quite precise, speedy, and is in good terms with the routine quality control process(Huynh et al., 2025a).
3.2.2 Liquid Chromatography–Mass Spectrometry (LC–MS / LC–ESI–MS/MS)
LC–MS chromatographic separation with the molecular detection capability of mass spectrometry. This makes it possible to accurately identify the molecular structure of semi-polar compounds such as flavonoid glycosides, alkaloids, triterpenoids, and phenolic esters. ESI facilitates the detection in both positive and negative ion modes that are compatible with complex phytochemical mixtures. (Costa De Camargo et al., 2025; El Sayed et al., 2020).
3.2.3 Gas Chromatography–Mass Spectrometry (GC–MS)
GC–MS is a technique that can be used to identify the volatile and low molecular weight compounds. Some of the components that P. guajava has and that GC-MS can detect are β-caryophyllene, 1,8-cineole, limonene, palmitic acid, and linoleic acid. Also, the comparison with NIST and Wiley libraries facilitates accurate confirmation of compounds (El Sayed et al., 2020; Huynh et al., 2025a).
3.2.4 Ultra-Performance Liquid Chromatography–Quadrupole Time-of-Flight–Mass Spectrometry (UPLC–QTOF–MS)
By combining UPLC-QTOF fast separation with high-resolution mass detection, it allows for metabolomics at the trace level. Besides, it can easily detect the minor phenolic derivatives and flavonoid glycosides besides giving the most preferable chemical fingerprint for the standardization process (Emam et al., 2025).
3.2.5 Nuclear Magnetic Resonance (NMR) Spectroscopy
NMR offers a non-destructive and highly detailed approach to the structural elucidation of both primary and secondary metabolites. With the help of NMR, the data obtained from LC–MS and GC–MS can be supported through the confirmation of the structural features of flavonoids, terpenoids, and phenolic acids (Emam et al., 2025).
Table 2. Major Analytical Methods for Characterization of Guava Leaf Phytochemicals
Chromatographic and spectroscopic instruments provide a thorough metabolomic profile of the leaves of Psidium guajava. HPLC is the one that measures phenolics, LC–MS/UPLC–QTOF–MS identify metabolites, GC–MS identifies volatiles and NMR confirms structures. They facilitate reliable standardization as well as bioactivity correlation when working together.
3.2 Validation Parameters
Validation of analytical methods is essentially setting the stage for the data obtained to be considered fair, trustworthy, and repeatable. As per ICH Q2(R1), AOAC, WHO, a process that stipulates the use of analytical methods to achieve their intended goals. Guava leaves which are made up of complex compounds and where co-elution of the matrix is very likely, validation determines the scientific robustness of each method thus it is the main point that data can be trusted for research, regulatory submission, and industrial usage (Emam et al., 2025; Huynh et al., 2025a).
Method Validation Purposes
3.3.1. Validation Parameters and Their Basis
Validation undertaken in compliance with worldwide standards (ICH Q2(R1), AOAC, WHO) serves to check if the new analytical routine can stand up to the challenge posed by its intended purpose. The plant extracts being highly complex and overlapping in phytochemical content. The validation not only supports the scientific robustness but also elevates the data quality for use in research, regulatory approval, and industrial application arenas (Emam et al., 2025; Huynh et al., 2025a).
Phytochemical validation of Psidium guajava extracts is the crucial to finding reliable analytical results. The key parameters are accuracy, precision, linearity, sensitivity (LOD/LOQ), recovery, robustness, reproducibility, and selectivity are the factors that confirm the methods such as HPLC, LC–MS, GC–MS, and UPLC–QTOF–MS are capable of generating reliable data.
3.4 Interpretation and Significance
1. Analytical profiling of Psidium guajava leaves confirms reliable, reproducible, and authentic phytochemical data.
2. Advanced tools (HPLC, LC–MS, UPLC–QTOF–MS, GC–MS, NMR) offer a complete chemical of major and minor bioactives.
3. Validation parameters such as accuracy, precision, linearity, robustness, reproducibility meets ICH Q2(R1), AOAC, WHO standards (Emam et al., 2025).
4. Higher phenolic/flavonoid content (HPLC, LC–MS) relates with antioxidant and anti-inflammatory effects.
5. Terpenes identified by GC–MS contribute to antimicrobial and antidiabetic activities.
6. Validated methods confirm quality assurance for guava extracts.
7. They provision the development of evidence-based, standardized herbal formulations.
8. Empower extensive applications in pharmaceutical, nutraceutical, and cosmeceutical industries.
4. Factors Affecting Phytochemical Yield and Composition
The qualitative and quantitative phytochemical aspects of biologically active substances in Psidium guajava leaf are affected by numerous genetic, environmental, and methodological factors. These factors is key to phytochemical recovery optimization and extract quality consistency (Huynh et al., 2025a; Imtara et al., 2025; A. Kumar et al., 2023; Mugao, 2024; Rawat et al., 2025).
4.2 Environmental Conditions
4.3 Harvesting Stage
4.5 Solvent Polarity and Extraction Time
4.6 pH and Temperature of Extraction Medium
5. Extraction Technologies
5.1 Conventional Extraction Methods
Conventional extraction methods refer to the traditional procedures, which have been used extensively to obtain bioactive compounds from plant-based materials. These methods mainly depend on solvent diffusion and solubility deviations of phytochemicals in plant tissues (Food Process Engineering and Technology Second Edition, n.d.). The main characteristic of extraction methods are maceration, percolation, and Soxhlet extraction.
Maceration is a straightforward technique that includes soaking a powdered plant in solvents (ethanol, methanol, ethyl acetate) at room temperature for 24-72 hours. The compounds are removed by diffusion. This method is suitable for thermolabile molecules (Bouchoukh et al., 2019). This method is simple and cheap but it is slow and produces lower yields than the advanced extractions, with the yields of 4.5% (chloroform) and 8.2% (ethyl acetate) being reported (Díaz-de-Cerio & Trigueros, 2025). Maceration is still a method of choice for many due to its ease, safety, and low operational cost (Bouchoukh et al., 2019).
Percolation is a variant of maceration that enables the continuous flow of the solvent through the plant material, thus improving mass transfer and extraction efficiency. In this process, the solvent is allowed to pass through a column or container full of plant material at a flow rate which is under control (Food Process Engineering and Technology Second Edition, n.d.). This method can also be used in large-scale production due to its reproducibility and the fact that solvent utilization is more efficient.
Soxhlet extraction is a continuous hot extraction process where the solvent is successively evaporated and condensed to remove the soluble compounds from the plant materials (Bai et al., 2015). The system enables fresh solvent to be continuously used to wash the sample, thereby ensuring complete extraction. Heat improves solubility and diffusion, thus Soxhlet method is especially good for the extraction of heat-stable compounds. Extraction times are usually between 6 and 48 hours depending on the solvent and the plant matrix (Bai et al., 2015). Even though Soxhlet extraction produces higher quantities of bioactive compounds than maceration or decoction (Ayembilla et al., 2023). Conventional extraction methods, which are the basis of phytochemical studies, are gradually being substituted or supported by advanced techniques that are characterized by higher yield, selectivity, and efficiency (Bhagya Raj & Dash, 2020; Sampath Kumar et al., 2021).
5.2 Modern Extraction Methods
5.2.1 Ultrasound-Assisted Extraction (UAE)
Ultrasound-Assisted Extraction (UAE) is a green, quick, and operative method of procurement of bioactive compounds from plant materials (Carreira-Casais et al., 2021). The method includes the use of ultrasonic waves (20–100 kHz) that produce cavitation bubbles in the solvent (Fu et al., 2020).
Major effects of ultrasound
Compared to conventional methods, UAE offers shorter extraction time, less solvent consumption, and higher yield (Chemat et al., 2017). The method is mostly safe for heat-sensitive and polar phytochemicals (Zhang et al., 2021). The UAE is determined by factors such as ultrasonic power, temperature, solvent polarity, extraction time, and solid-to-solvent ratio which must be optimized carefully (Kong et al., 2015; Vajira Bulugahapitiya et al., 2024).
5.2.2 Microwave-Assisted Extraction (MAE)
Microwave-Assisted Extraction (MAE) is a fast, energy-efficient method that employs non-ionizing electromagnetic waves (300 MHz–300 GHz) to separate bioactive compounds from plants. The microwaves heat the material through ionic conduction and dipole rotation, which breaks the cell walls, increases porosity, and releases the intracellular compounds, thus intensifying the mass transfer and the yield (Szliszka et al., 2009). The performance of MAE is dictated by the dielectric characteristics of the solvent and plant material (Gil-Martín et al., 2022). To attain an optimum balance between the yield and stability of the compounds (Frosi et al., 2021; Gupta et al., 2024; Vlachoudi et al., 2023). MAE yields are very high, in comparison with less solvent is required and energy consumption is low, while the time of extraction is significantly shortened when compared with conventional methods (Valisakkagari et al., 2024a). Phenolics and pectins extraction from the fruit by-products such as pomelo, tangerine, pineapple, and banana peels have been the subject of research works applying MAE (Benmebarek et al., 2024; García-Martín et al., 2023). It demonstrated a green score (GS) of 0.49 at the point of 1.8 min extraction, thus indicating low energy consumption and high efficiency(Mali & Kumar, 2023).
5.2.3 Enzyme-Assisted Extraction
Enzyme-Assisted Extraction (EAE) is a green, and non-thermal procedure that involves using specific enzymes to dismantle plant cell walls and, in this way, set free bioactive compounds in a very short time (Boateng & Clark, 2024). The cellular walls are hydrolyzed by the enzymes cellulases, hemicellulases, pectinases, and proteases, and the transmission of mass along with permeability is enlarged (Barbosa et al., 2021; Łubek-Nguyen et al., 2022). EAE hinges on features such as enzyme type, concentration, temperature, pH, extraction time, and particle size. Conditions that are gentle (≈40 °C, optimal pH) facilitate enzyme activity and the production of thermolabile compounds is still possible (Fatima et al., 2024; Valisakkagari et al., 2024a). EAE can boast of great features such as the use of green solvents (water/buffers), low energy consumption, high selectivity, and the integrity of the compounds being preserved. It is performed in a simple apparatus and is a way of producing phenolics, flavonoids, lipids, proteins, and pectins from different plant wastes. The principles of green chemistry, EAE is very mild and sustainable and, therefore, does not produce much waste and has a low impact on the environment (Gómez-García et al., 2012).
5.2.4 SFE (Supercritical Fluid Extraction)
Supercritical Fluid Extraction (SFE) is an innovative extraction technique that requires a solvent to be in its supercritical state which means that the temperature and pressure have to be beyond the critical point (Tc and Pc) (Casquete et al., 2022). The extraction method is based on the principle of diffusion of solutes from the solid matrix into the extraction medium (Díaz-de-Cerio & Trigueros, 2025).
Parameters of SFE
The effectiveness of SFE is controlled by various factors - The pressure, the temperature, the flow rate, the extraction duration, the particle size and the use of co-solvent.
SFE has many features that make it superior to traditional solvent extraction (Díaz-de-Cerio & Trigueros, 2025). SFE is a green technology in line with green chemistry principles through the use of non-toxic CO₂, the near elimination of solvent waste, and the production of quality bioactives (Díaz-de-Cerio & Trigueros, 2025; Romano et al., 2021, 2022).
Table: Extraction Technologies
|
Technologies |
Method |
Principle & Mechanism |
Advantages |
Disadvantages |
Yield Data |
|
Conventional |
Maceration |
Soaking plant material in solvent at room temp for diffusion-based extraction. |
Simple, inexpensive, safe for thermolabile compounds. |
Time-consuming, low yield. |
Guava leaf: 4.5–8.2% yield (chloroform–ethyl acetate). |
|
|
Percolation |
Continuous solvent flow through plant bed enhances mass transfer. |
Higher efficiency, reproducible, scalable. |
More equipment and solvent use. |
Widely used for industrial extracts. |
|
|
Soxhlet Extraction |
Continuous hot extraction via repeated evaporation-condensation cycles. |
Complete extraction, higher yield, efficient solvent use. |
Long time, high energy, not eco-friendly. |
Psidium guajava: 1.8–8.07% yield (methanol best). |
|
Modern / Green |
Ultrasound-Assisted Extraction (UAE) |
Cavitation bubbles disrupt cell walls, improving diffusion. |
Short time, low solvent, high yield, eco-friendly. |
High power may degrade compounds. |
Psidium guajava polysaccharides: 9.2% yield. |
|
|
Microwave-Assisted Extraction (MAE) |
Microwaves heat solvent and matrix through dipole rotation and ionic conduction. |
Very fast, energy-efficient, high yield, scalable. |
Risk of overheating/degradation. |
Green score (GS): 0.49 (efficient). |
|
|
Enzyme-Assisted Extraction (EAE) |
Enzymes degrade cell wall polymers, freeing bioactives. |
Mild, selective, non-thermal, preserves bioactivity. |
Enzymes costly, may deactivate. |
GS = 0.1–0.54; high selectivity and yield. |
|
|
Supercritical Fluid Extraction (SFE) |
CO₂ at supercritical conditions dissolves and extracts solutes efficiently. |
Solvent-free, pure extracts, eco-friendly, selective. |
Expensive equipment, high pressure. |
GS = 0.49 ± 0.09; moderately green. |
Extraction technologies have different stages in depuration of bioactive compounds. They go from very slow and solvent-consuming traditional methods to very fast and solvent-free techniques. Modern methods such as UAE, MAE, EAE and SFE allow obtaining higher yields, selectivities and efficiencies in less time and with less solvent.
6. Synergistic and Molecular Insights
6.1 Synergistic Effects Among Bioactives
6.2 Molecular docking studies
Computational molecular docking is a structure-based approach used to predict the preferred orientation of a ligand within the binding site of a target protein. Docking simulations evaluate ligand–protein interactions using scoring functions that estimate binding affinity and complex stability. These studies help in identifying potential inhibitors by analyzing interaction strength, binding pose, and energetic favorability, thereby supporting drug discovery and lead optimization processes (Bhagat et al., 2021; Saber et al., 2021).
6.3 Mechanistic pathways and enzyme target interactions
Guava bioactives primarily intervene antioxidant and anti-inflammatory processes by directly targeting enzymes and cellular signaling molecules. These action routes eventually lead to the alleviation of oxidative stress and the reduction of inflammatory mediator release (Huynh et al., 2025b).
Thus, these actions, which interplay, result in skin and tissue protection, prevention of cellular damage, and the induction of inflammatory conditions healing acceleration (Huynh et al., 2025b).
7. Recent Trends and Innovations (2023–2025)
7.1 Nanotechnology integration
7.3 Green extraction and eco-friendly formulation design
7.4 Advances in cosmeceutical and pharmaceutical applications
8. Challenges and Future Perspectives
8.1 Standardization and clinical validation
A major challenge in guava-based formulations is variability in phytochemical composition due to differences in source, processing, and extraction methods. Although standardization parameters for simplicia and extracts have been established, their consistent application remains limited. In addition, the lack of sufficient clinical validation restricts therapeutic translation. Future efforts should focus on harmonized standardization protocols and well-designed clinical studies to ensure safety, efficacy, and regulatory acceptance (Suswidiantoro et al., n.d.).
8.2 Bioavailability and stability issues
The guava leaf bioactive, e.g. the flavonoids and polyphenols, are insoluble, have low penetration through the skin, and are readily degraded by atmospheric factors, therefore its therapeutic value in ointments is highly restricted. Nanotechnology-based delivery platforms such as nano emulsions, liposomes and polymeric nanoparticles can enhance solubility and sustained release to improve skin absorption (Khare et al., 2024).
8.3 Regulatory limitations
A significant hurdle in guava crop regulation is the lack of harmonized global and local standards, which complicates international trade and quality consistency. While conventional methods are well-established, the integration of modern techniques like genetic engineering faces strict regulatory and ethical scrutiny, limiting their widespread therapeutic and commercial acceptance. Additionally, mandatory adherence to environmental laws regarding pesticide use, water quality, and waste management remains a complex challenge for farmers. Future progress depends on creating unified standardization protocols and supportive legal frameworks to ensure safety, sustainability, and market competitiveness (Yadav et al., 2023).
9. Future Research and Directions
Research on the subject ought to primarily be done on large and well-controlled clinical trials that would substantiate the safety, dosage and efficacy of guava ointments. The predictions of bioavailability, stability, and release profiles can be improved with the assistance of AI, which can help in formulation.
9.1 Large-Scale Clinical Studies and Dosage Optimization
The future studies must mostly involve large, controlled, clinical trials that will establish the safety, dosage and efficacy of guava ointments. Bioavailability, stability as well as release behavior can be better predicted using AI-driven formulation tools. These will have the potential to accelerate the creation of the optimized nano-ointments significantly (Bouchoukh et al., 2019; Łubek-Nguyen et al., 2022).
9.2 Advanced Formulation Research with AI Integration
The AI and machine learning tools can significantly simplify the research on the formation of the guava ointment as it will be able to simulate the interactions of the scientific elements and to predict the stability, permeability, and release kinetics (Dirgule et al., 2025).
Synergistic action of complementary herbal constituents can have a great impact in enhancing the therapeutic effects of the guava leaf extracts. Pytochemicals interactions can be predicted with the help of molecular docking. In vitro studies can confirm the presence of synergistic interactions. Multi-herbal formulation efficacy can become a guide in in vivo studies (Huynh et al., 2025b).
The extracting green methods are ultrasound-, microwave-, supercritical fluid-, and enzyme- assisted. Their production is still in a phase as they require to be refined further to enhance the purification and the yield of phytochemicals of guava. The project is being undertaken to ensure that the minimal effects of production on the environment are realized (Valisakkagari et al., 2024b).
The steps to take next should involve the potential more advanced delivery methodologies like nanoplarticles with stimuli-sensitive abilities, microneedle patches, transdermal systems as well as bioadhesive polymers that have the capabilities to allow penetration or retention of guava bioactives in specific parts of the skin(Chiari-Andréo et al., 2017; Valisakkagari et al., 2024b).
CONCLUSION
Guava (Psidium guajava L.) leaves can be seen as a significant ethnomedicical and phytopharmacological source, being a potential attractive therapeutic agent. The first thing to come to mind as their bioactive substances are the flavonoids, the phenolic acids, the tannins, the terpenoids, the alkaloids, the essential oils, the minerals, and the vitamins, which are the major contributors to the pharmacological versatility because the activities mentioned cover a wide range of antioxidant, antimicrobial, anti-inflammatory, antidiabetic, anticancer, hepatoprotective, cardioprotective, and hair growth–promoting. The chemical analysis and the quality standardization of the guava-derived products are very much facilitated by the application of advanced instrumental techniques such as HPLC, LC–MS, GC–MS, UPLC–QTOF–MS, and NMR. Phytochemical production is largely determined by genetics, environment, and methodology parameters, thus there is a necessity for the standardization of harvesting, drying, and extraction stages. Present-day extraction methods—UAE, MAE, EAE, and SFE—are not only more productive and environmentally friendly than the traditional ones but also make it possible to achieve better yields with proper preservation of heat-sensitive substances. Guava leaves, in general, are a renewable, naturally decomposable, multifunctional material of nature-derived bioactives with major consequences for the contemporary pharmaceutical, nutraceutical, cosmeceutical, and food sectors. The ongoing research on metabolomics, formulation, standardization, and clinical validation will, in fact, facilitate their move from historically folk medicine to scientifically proven modern applications.
REFERENCES
Jannatul Firdaus*, Khushi Rastogi, Anshika Yadav, Tanlaka Nuradin Fonyuy, Shahnawaz Ahmad, Guava (Psidium guajava L.) Leaf Bioactives: From Phytochemical Characterization to Therapeutic and Technological Applications, Int. J. Med. Pharm. Sci., 2026, 2 (5), 310-328. https://doi.org/10.5281/zenodo.20073557
10.5281/zenodo.20073557