American Journal of Food and Nutrition, 2017, Vol. 5, No. 4, 115-120 Available online at http://pubs.sciepub.com/ajfn/5/4/1 ©Science and Education Publishing DOI:10.12691/ajfn-5-4-1 Comparative Studies of the Phytochemical, Antioxidant and Antimicrobial Properties of Cashew Leaf, Bark and Fruits Extracts John O. Onuh * , Gabriel Idoko, Peter Yusufu, Felicia Onuh Department of Food, Nutrition & Home Sciences, Kogi State University, Anyigba, Kogi State, Nigeria *Corresponding author: onuh.jo@ksu.edu.ng Abstract Extracts of the leaf, stem bark and fruit of cashew plants were investigated to determine their phytochemical, antioxidant and antimicrobial properties. Cashew leaves, stem barks and fruits of the Brazilian Jumbo variety were processed, extracted and analyzed for their phytochemical, antioxidant and antimicrobial activities. The results showed that the phytochemical contents varied significantly between the sample extracts. Carotenoids content of cashew extracts are 88.86, 125.93 and 100.33 mg/g for the leaf, bark and fruit respectively. The stem bark extract showed significantly highest tannin content (2.01 mg/g) compared to the cashew fruit extract (1.56 mg/g) and cashew leaf extract (1.19 mg/g). Total phenolic content of the cashew plant parts varied significantly from 103.92 – 983 .23 mg/g sample of the extract with the leaf extract having significantly lowest value while the fruit had the highest value. Cashew fruit extract exhibited significantly highest percentage DPPH scavenging activity at all concentrations. There was a positive correlation between the total phenolic content and antioxidant activities of cashew extracts suggesting that the phenolic content may directly influence the antioxidant activities. Extracts of cashew leaves and stem barks exhibited appreciable inhibition on all human pathogens screened compared to the fruit extract which was only active against salmonella typhi. Cashew extracts could therefore be used as a potential source of ingredients in the development of nutraceuticals and functional foods for the control, management and treatment of health disorders. Keywords: cashew, extracts, antioxidant, phytochemical, functional foods, antimicrobial Cite This Article: John O. Onuh, Gabriel Idoko, Peter Yusufu, and Felicia Onuh, “Comparative Studies of the Phytochemical, Antioxidant and Antimicrobial Properties of Cashew Leaf, Bark and Fruits Extracts.” American Journal of Food and Nutrition, vol. 5, no. 4 (2017): 115-120. doi: 10.12691/ajfn-5-4-1. 1. Introduction Plants have a wide variety of medicinal potentials that has remained greatly untapped. This has generated huge and renewed interest in ethnomedicine, ethnobotany and ethnopharmacology [1]. Extracts from these plant parts (especially the roots, stems, leaves and fruits) have been used extensively to treat infectious diseases and inflammatory and oxidative stress related conditions [2,3,4]. Traditional medicinal plants have the ability to synthesize a wide variety of chemical compounds that play a major role in primary health care as therapeutic remedies. Additionally, they serve as alternative sources for western medicines that are expensive, synthetic and as consequence, may have adverse side effects [2,5]. Chemical compounds in plants mediate their effects on the human body through processes identical to those in conventional drugs [2]. The cashew tree (Anacardium occidentale L) is one such plant with potentials for use as a medicinal plant. It belongs to the family of the flowering plant, Anacardiaceae, whose leaves and/or the stem barks have been used for treatment of eczema, diarrhea, dysentery, colonic pains, genital problems, venereal diseases, impotence, bronchitis, cough and syphilis-related skin disorders [6,7]. It has also been reported to possess anti-diabetic, anti-inflammatory anti-microbial and anti-ulcerogenic properties [8]. These bioactivities may be attributed to the presence of secondary metabolites (including flavonoids, phenols, phenolic glycosides, saponins and glycosides) on the plant [9,10]. These compounds however, differ widely in their structure, biological activities and mechanisms of actions, and consequently may modulate different pathways. Many researchers have reported that medicinal plants contain various bioactive components that exhibits antioxidant and anti-microbial activities with beneficial health effects [9,11,12,13]. Oxidative stress has been implicated in the development of chronic and degenerative ailments such as cancer, autoimmune disorders, rheumatoid arthritis, cataract, aging, cardiovascular and neurodegenerative diseases [9,14,15]. Antioxidants are chemical compounds that reacts with and neutralize free radicals generated in biological systems during cellular metabolism, thus preventing them from causing damage [12]. Natural antioxidants are however gaining desired attention for their ability to protect the human body from these free radicals mediated oxidative stress reactions [9,14].