Chemical Constituents of Secondary Metabolites of Medical Importance in Guava Plant (Psidium guajava)
Background
The guava plant (Psidium guajava L.), a member of the Myrtaceae family, is a tropical evergreen shrub widely acknowledged for its diverse array of secondary metabolites with notable medicinal value. These bioactive compounds are predominantly found in the leaves, fruit peel, bark, and roots (Kumar et al., 2021). Among them are flavonoids such as quercetin, guaijaverin, kaempferol, and avicularin, which function as powerful antioxidants by neutralizing free radicals and mitigating oxidative stress linked to chronic conditions including diabetes and cardiovascular diseases (Huynh et al., 2025).
In addition, phenolic acids—such as gallic acid, ellagic acid, caffeic acid, and ferulic acid—play a crucial role in anti-inflammatory activity by inhibing enzymes like COX-2 and regulating cytokine production. These properties support the plant’s traditional use in managing gastrointestinal disorders, arthritis, and wound healing (Sahal, 2025). Tannins and saponins further contribute to guava’s medicinal profile through their strong antimicrobial effects, which involve disrupting microbial cell membranes and inhibiting pathogens such as Staphylococcus aureus and Escherichia coli, thereby justifying its historical application in treating infections and diarrhea (Al-Rimawi, 2025).
Terpenoids, including β-caryophyllene, limonene, and caryophyllene oxide, along with essential oils, exhibit a wide range of pharmacological activities such as analgesic, anticancer, and antidiabetic effects. These compounds act through mechanisms like induction of apoptosis in cancer cells, modulation of pain pathways, and enhancement of insulin sensitivity (Zou, 2023). Furthermore, the high content of ascorbic acid in guava enhances immune response and collagen synthesis. The combined and synergistic interactions among these metabolites significantly strengthen the plant’s overall therapeutic potential (Butt, 2025).
Despite substantial in vitro and preclinical evidence demonstrating antioxidant, antimicrobial, anti-inflammatory, antidiabetic, and anticancer properties, several research gaps hinder the clinical application of guava’s secondary metabolites (Ugbogu et al., 2022). One major limitation is the lack of large-scale, randomized controlled human trials to confirm efficacy, determine optimal dosages, assess long-term safety, and validate therapeutic outcomes, as most current findings rely on animal studies or observational data (Tousif et al., 2022).
Moreover, variations in metabolite composition due to regional differences, environmental conditions, soil characteristics, and cultivation practices remain insufficiently explored. This limits the identification of superior chemotypes and the development of standardized pharmaceutical extracts (Emam, 2025). The influence of extraction techniques, processing methods, and strategies to enhance bioavailability on compound stability and absorption is also not well understood, posing challenges for the formulation of effective nutraceuticals and drugs (Sahal, 2025).
Additionally, there is limited understanding of synergistic interactions among these bioactive compounds, potential drug interactions, toxicity profiles across diverse populations, and emerging therapeutic applications. Metabolomics-based studies, including the valorization of byproducts, also require further investigation (Huynh et al., 2025). Addressing these gaps through advanced clinical research, metabolomic approaches, and interdisciplinary studies is essential to bridge the gap between traditional medicinal use and evidence-based practice, thereby unlocking the full potential of guava as a sustainable therapeutic resource.
