Total phenolic and flavonoid contents, and in vitro antihypertension activity of purified extract of Indonesian cashew leaves (Anacardium occidentale L.)

Cashew tree (family Anacardiaceae) grows widely in many areas of the Southeast Asia countries including Indonesia. Its fruit and nut are used for food, whereas its leaf is one of the traditional antihypertensive medicine in Indonesia. Hypertension affects many people around the world especially in developing countries such as Indonesia. The study aimed to evaluate the in vitro antihypertension effect of purified extract of cashew leaves (PECL) using an isolated organ technique, and determine the total phenolic and flavonoid contents. The results showed that PECL at 0.5 and 1.0 mg/mL was obviously able to inhibit the contraction of isolated rat aorta induced by cumulative addition of phenylephrine. The inhibitory effect of PECL were 25.72±8.19% and 39.60±3.50% (p<0.05), respectively. PECL (1.0 mg/mL) also changed the pD2 value of phenylephrine from 6.71±0.37 to 5.93±0.33 (p<0.05), and relaxed the isolated-organ mildly by 13.11±0.72%. In addition, PECL contained the total phenolic of 19.78±0.62% and the total flavonoids of 1.97±0.04% which are equivalent to gallic acid and rutin, respectively.