Bioprospecting of katang-katang leaves (Ipomoea pes-caprae) from Sumba Island, East Nusa Tenggara: antimicrobial, antioxidant and secondary metabolites content

Ipomoea pes-caprae (Katang-katang) is one of the vegetations that grows in coastal area. Previous studies have proven that I. pes-caprae showed antibacterial, anti-inflammatory, and antioxidant properties. This research was conducted to characterize secondary metabolites content, antimicrobial activity and antioxidant activity of I. pes-caprae crude extract from Sumba, East Nusa Tenggara. The extraction was carried out using consecutive extraction method using n-hexane, ethyl acetate, and methanol with agitation (115 r.p.m for 24 hours). Phytochemical test and thin layer chromatography were performed to analyse the secondary metabolites in I. pes-caprae . In addition, total phenolic content (TPC) was calculated using Folin-Ciocalteu method. The antimicrobial activity was conducted using paper disc diffusion method against Bacillus cereus, Salmonella typhi, Escherichia coli, Micrococcus luteus, Candida albicans , and C. tropicalis . Phytochemical test and TLC analysis showed that n-hexane extract contained flavonoid, tannin, and steroid; ethyl acetate extract contained alkaloid, flavonoid, and terpenoid; while methanol extract contained alkaloid, tannin, and steroid. The antimicrobial activity gave negative results against all microbial pathogen. The ethyl acetate and methanol extracts were noted as a strong antioxidant agent with IC50 values of 65.7 ppm and 81.8 ppm. Moreover, TPC in each extract was 3.7 mg GAE/g in n-hexane extract, 6.4 mg GAE/g in ethyl acetate extract and 8.9 mg GAE/g in methanol extract.