Abstract

Several medicinal plants in Northern Thailand have been used for inflammatory symptom and various diseases by traditional practitioners for a long time without the scientific data supported. Ceasalpinia sappan Linn. is a medicinal plant cultivated in Northern Thailand and has been used for various disease treatment especially inflammatory symptom, arthritis and cancer. The heartwood of C. sappan was extracted with 95% ethanol and concentrated under reduced pressure. The extract was studied for free radical scavenging activity on ABTS^·+, superoxide anion, nitric oxide and total phenolic content. In addition, the extract was studied on protective effect on DNA damage-induced by hydroxyl radical. C. sappan extract exerted strong scavenging activity on ABTS^·+ with the VCEAC = 0.5782±0.0042 gram L-ascorbic acid/gram extract and TEAC = 0.9159±0.0055 gram Trolox/gram extract. C. sappan extract also exhibited high scavenging activity on superoxide anion with an EC₅₀ value of 7.73±0.06 µg/ml, which was comparable to the activity of L-ascorbic acid and rutin (EC₅₀ value of 6.65±0.07 and 7.83±0.13 µg/ml, respectively). Furthermore, it exerted the strong activity on nitric oxide scavenging activity with an EC₅₀ value of 4.24±0.14 µg/ml. This activity was comparable to curcumin with an EC₅₀ value of 5.70±0.08 µg/ml. It also contained high amount of phenolic content with the gallic acid equivalent = 0.5540±0.0192 mg gallic acid/mg extract. C. sappan extract also showed the protective effect on DNA damage-induced by hydroxyl radical. According to the strong activity on free radical scavenging in vitro and protective effect on DNA damage-induced by hydroxyl radical, C. sappan has the potential for chemopreventive study.

Key words: Caesalpinia sappan L., antioxidant activity, DNA damage, superoxide anion, nitric oxide.