Inhibitory Activity of Kaempferia galanga and Hibiscus sabdariffa on the Rate of PGH2 Formation

Abstract

Cyclooxygenase (COX) or Prostaglandin H2 Synthase (PGHS) is the enzyme that catalyzes the first two steps in the biosynthesis of prostaglandins from the substrate, arachidonic acid. The NSAIDs work by inhibiting both COX isoforms, thus the conversion of arachidonic acid into prostaglandin is disturbed. In our country, kaempferia rhizome (Kaempferia galanga) and roselle calyx (Hibiscus sabdariffa) are used to reduce inflammation by consuming herb tea of these plants. This work studied the inhibitory activity of kaempferia rhizome and roselle calyx on the rate of prostaglandin formation by measuring the absorbance of TMPD (tetramethyl-p-phenyldiamine) oxidized by the extracts, against time. The plants were collected from Manoko plantation in West Java. Phytochemical screening showed that the rhizome contains quinones and terpenes, while the calyx contains polyphenol, flavonoid, quinone and saponin. 100 g of dried rhizome and calyx were separately boiled in 1 L of distilled water for 15 min at 90°C, freeze-dried and dissolved in ethanol 96%. Both Kaempferia galanga and Hibiscus sabdariffa showed inhibition on PGH2 formations. The rate of PGH2 formations on COX-1 was lower than on COX-2. These plants could be further developed for anti-inflammatory drug.