Anti-inflammatory activity of isolated compounds from the stem bark of Garcinia cowa Roxb

Objective: To find the anti inflammatory active compounds from methanol extract of Garcinia cowa. Methods: To evaluate the inhibitory activity of isolated compounds on nitric oxide (NO) production, culture media was assayed using Griess reaction. An equal volume of Griess reagent (1% sulphanilamide and 0.1% N-(L-naphthyl)-ethylene diamine dihydrochloride, dissolved in 2.5% H3PO4) was mixed with culture supernatant and color development was measured at 550 nm using a micro plate reader. The amount of nitrite in the culture supernatant was calculated from a standard curve (0–100 μM) of sodium nitrite freshly prepared in deionized water. Percentage of the NO inhibition was calculated by using nitrate level of IFN-γ/LPS-induced group as the control. Results: Isolated compounds, tetraprenyltoluquinone, rubraxanthone and α-mangostin from stem bark of Garcinia cowa Roxb were evaluated for their anti-inflammatory activity. Only α-mangostin exhibited strong anti-inflammatory activity with 83.42 % inhibition of NO and without inducing severe cytotoxicity at 50 μM. Rubraxanthone showed weak inhibition of NO with 23.86 % inhibition of NO while maintained 77.32 % of cell viability. TPTQ also showed the strong inhibition of NO with 80.98 % inhibition but unfortunately this compound also induced severe cytotoxicity with 39.62% viability. Conclusion: α-Mangostin exhibited strong anti-inflammatory activity without inducing severe cytotoxicity at 50 μM. Rubraxanthone showed weak inhibition of NO while Tetraprenyltoluquinone also showed the strong inhibition of NO however this compound also induced severe cytotoxicity.