Exploring the Polyphenol Contents and Antioxidant Capacity of the Leaf Extracts of Selected Indonesian Syzygium Species

Abstract

Some plants belonging to the Myrtaceae family are various guavas from the Syzygium genus, such as Syzygium samarangense (Blume) Merr. & L.M. Perry (SS), Syzygium malaccense (L.) Merr. and Perry. (SM), and Syzygium aqueum (Burm.f.) Alston (SA). These three guavas are easy to obtain and are widely grown in Indonesia. These three guava leaves have pharmacological properties similar to those of PG leaves. The genus Syzygium has traditionally been used to treat diarrheal disorders, diabetes, inflammation, bronchitis, and acid reflux/ulcers. 1 This genus has been scientifically proven to have antioxidant, antimicrobial, antifungal, antiviral, analgesic, anti-inflammatory, antihypertensive, antihyperglycemic, sedative, and spasmolytic activities. [5][6][7] Several pharmacological studies have reported that SS, SM, and SA have antioxidant and antimicrobial activities. [8][9][10][11] The phenolics, flavonoids, and tannins in the polyphenolic content of Syzygium species contribute to their antioxidant activity. The profile of these metabolites in the plant extracts can easily be studied using thinlayer chromatography (TLC) techniques. The present study therefore, is aimed at investigating the polyphenolic contents in terms of total phenolic, flavonoids, and tannins in the leaves of three selected Syzygium species and evaluate their antioxidant activity in comparison to PG leaves. Materials and Methods Plant materialsThe four types of guava leaves were collected from the Duren Sawit district (East Jakarta) in February, 2022. The plant sample was identified, authenticated, and given a voucher number B-571/DI.05.