Evaluation of Phytochemicals, Total Phenolic Content, Antioxidant, and Antimicrobial Activities of Philippine Forest Woody Vines

Woody vines are herbaceous plants that use different clinging structures to find vertical support from nearby trees. They are commonly used for handicraft purposes but there were reports that they were used for medicinal applications. With this, the stems of eight forest woody vine species were evaluated for their phytochemical components, total phenolic content, antioxidant, and antimicrobial activities. These were Strychnos minor Denrst. (“balakbakin”), Arcangelisia flava (L.) Merr (“albotra”), Merremia peltata (L.) Merr. (“bulakan”), Hypserpa nitida Miers ex Benth (“lalapau”), Symphorema luzonicum (Blanco) F.-Vill. (“mulawing-baging”), Dicranopteris linearis (Burm. f.) (“tilob”), Connarus semidecandrus (Zoll.) Leenh. (“kamagsa brown”), and Entada phaseoloides (L.) Merr (“gugo”), which are all native to the Philippines. Results showed that S. minor and S. luzonicum had the highest extraction yield of 6.28 ± 0.39% and 6.26 ± 0.77%, respectively. Phytochemical screening revealed that the crude extracts contained different phytochemicals such as alkaloids, steroids, terpenoids, and tannins. For total phenolic content, ethanolic extracts of woody vines ranged from 9.51–640.24 mg GAE/g dried extract with C. semidecandrus and S. luzonicum were found to have higher amounts among forest woody vines with values of 640.24 ± 7.13 and 398.94 ± 20.08 mg GAE/g dried extract, respectively. Moreover, DPPH results showed that D. linearis, S. luzonicum, E. phaseoloides, and C. semidecandrus had strong antioxidant activities, which ranged from 5.99–17.88 μg/mL IC50 and were higher than the butylated hydroxytoluene (BHT) standard (28.47 μg/mL IC50). On the other hand, M. peltata, A. flava, H. nitida, and S. minor antioxidant activity ranged from 40.61–78.65 μg/mL IC50. Similar results of FRAP assay showed that S. luzonicum had the highest antioxidant activity with 2.68 ± 0.07 μmol TE/g dried extract, whereas S. minor and H. nitida had the lowest antioxidant activity with 0.43 μmol TE/g dried extract ± 0.03 and 0.41 ± 0.02 μmol TE/g dried extract, respectively. Among the tested microorganisms for antimicrobial assay (well diffusion method), the growth of S. aureus was susceptible to the ethanolic extracts of S. luzonicum and C. Semidecandrus with inhibition zones of 21.3 ± 1.4 and 20.1 ± 2.5 mm, respectively. Overall, results show that woody vines contain phytochemicals with promising antioxidant and antimicrobial properties. These results could be used as a baseline in the purification of woody vines’ bioactive components.