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Journal of Thai Traditional & Alternative Medicine Vol. 7 No. 2 May-August (Supplement) 2009 ÒÒÛ

PP-4

Free radical scavenging activity and phytochemical constituents of methanolic

extracts of traditional medicinal plants for hypoglycemic treatment in the
North of Thailand

1, 3 1, 2 1, 2
Zaruwa, Z. Moses , Aranya Manosroi , Jiradej Manosroi
1
Faculty of Pharmacy, Chiang Mai University, Chiang Mai, Thailand, 50200
2
Natural Products Research and Development Center (NPRDC), Science and Technology Research Institute, Chiang Mai
University, Chiang Mai, Thailand, 50200
3
Faculty of Science, Adamawa State University, P.M.B 25, Mubi, Adamawa State, Nigeria

Rationale: Oxidative stress resulting from complications of diabetes mellitus is known to cause the

creation of free radicals in the body of diabetic individuals. Medicinal plants are among the popular remedies for
the treatment of diabetes mellitus. The free radical scavenging activity of plant extracts is considered an
important feature of hypoglycemic medicinal plants. This work has evaluated the free radical scavenging

activity as well as the phytochemical constituents of the methanolic extracts of the selected 11 Thai Lanna
plants from the database which have been traditionally used for treatment of diabetes namely; Anogeissus
acuminata var. lanceolata, Catunaregam tomentosa (DC.) Tirveng (maj teen), Dioecrescis erythroclada (Kurz)
®
Tirveng (Ma khang daeng), Yamed Boraped Pungchang , Mai Tau Lusi, Dendrophthoe pentandra (L.) Miq (Ka
fak ma muang), Mimosa pudica Linn. var. hispida Bren (Mai ya rab), Moringa pterygosperma C. F. Gaertner (Ma

room), Pterocarpus macrocarpus kurz (Pra doo), Solanum laciniatum australia (Ma khuea Australia), Solanum
torvum SW.(Ma khuea phuang).
Methodology: 1, 1-diphenyl -2-picrylhydrazyl (DPPH) assay for free radical scavenging activity and the

standard phytochemical assay for the bioactive constituents in the plant extracts were used.
Results: In the DPPH assay, Anogeissus acuminata var. lanceolata gave the highest activity of 7.3 folds

more than vitamin E (SC50 = 51 ± 0.001 mg / ml), whereas Dendrophthoe pentandra (L.) Miq, Pterocarpus
macrocarpus Kurz showed significantly (P <0.05) higher activity of 1.8 more than the standard. Mai Tau Lusi
however was comparable to the standard. Phytochemical analysis of the methanolic extracts from these 4 plants

indicated higher contents of glycosides, xanthones and tannins than other phytochemicals.
Conclusion: The results have suggested the relationship between the free radical scavenging activity and
the traditional use of these plants in diabetes by the Thai people in the Lanna region of Thailand. The contents

of glycosides, xanthones and tannins may be responsible for antioxidative and antidiabetic activity of the 4
selected plants, especially A. acuminata.
Keywords: hypoglycemic, free radical scavenging activity, phytochemicals, Lanna