Identification of phenolic compounds and evaluation of biological activities of methanolic extracts obtained from two varieties of longan (dimocarpus longan) peels
Chantarasaka, S., Chareonsap, P. P. and Poeaim, S.
Dimocarpus longan belongs to the Sapindaceae family, which are revealed as
cryptic species. In Thailand, Dimocarpus longan spp. longan var. longan such as Edor is
the most cultivated. Another Dimocarpus longan spp. longan var. obtusus (Dimocarpus
obtusus), called Lum-Yai Thao, is found in Eastern Thailand. However, there is still little
information on the biological activity of Thao. Hence, this research was designed to
identify phenolic compounds and evaluate the biological activities of methanolic extracts
obtained from peels of two longan varieties: Edor VS Thao. For the total phenolic
compound, no significant differences were observed between Edor and Thao. For
antioxidant activity using DPPH, ABTS, and FRAP assays, the analogs showed Edor had
more activity than Thao. The disc diffusion test at 5 mg/disc showed that Edor peels extract
effectively inhibited the growth of bacteria, but not Thao extracts which were strong
against Propionibacterium acnes. However, both of them also did not have activity against
Escherichia coli and Staphylococcus epidermidis.For anti-tyrosinase activity, both variety
extracts had less effective anti-tyrosinase activity.ETC...