Study on the scavenging DPPH radical inhibitory activity of some medicinal plants collected at Ma Da forest, Dong Nai province - Nguyen, Hai Xuan; Le, Tho Huu; Do, Truong Nhat Van; Nguyen, Thy Anh; Nguyen, Mai Thanh Thi (VNUHCM Journal of Advanced Research in Natural Sciences, 2022)