Qualitative phytochemical profiling, and in vitro antimicrobial and antioxidant activity of Psidium guajava (Guava)

Psidium guajava is a well-known tropic tree, widely cultivated for its fruits, and traditionally, it has long been used for medicinal purposes. For instance, its fruit peels are also being used to alleviate stomach cramps in Namibia and its leaves-derived aqueous extract are used to treat Candidiasis (yeast infection) caused by Candida albicans in some parts of the world. Therefore, this study identified the phytochemical compounds in Psidium guajava leaf and fruit peels extracts, determined its antioxidant and antimicrobial activities. Psidium guajava leaves and fruit peels extracts were obtained using five solvents (Acetone, methanol, aqueous acetone, aqueous methanol and water) via maceration and boiling extraction methods. The extracts were then subjected to phytochemical screening, Gas chromatography-Mass spectrometry, Fourier Transform Infrared Spectroscopy, antioxidant, and antimicrobial analyses (against pathogenic bacteria: Escherichia coli, Salmonella spp., Staphylococcus aureus and fungus; Candida albicans). The qualitative phytochemical screening revealed the presence of alkaloids, flavonoids, phenols, tannins, steroids, saponins and terpenoids, and some of their associated functional groups were revealed by Fourier transform infrared spectroscopy analysis. Gas chromatography-Mass spectrometry analysis identified various compounds with antimicrobial and antioxidant properties. The different crude extracts exhibited varying inhibitory effects against the selected pathogens, with the leave extracts exhibiting the highest antimicrobial activity whereas, the peel extract exhibited the highest antioxidant activity. This study thus highlights Psidium guajava's intriguing therapeutic contribution towards the survival of humankind and it can be strategized for future use to treat pathogenic bacterial diseases.