1. Introduction Isodon is widely distributed and important genus of the family Lamiaceae. Various diterpenoids with diverse structures had shown antibacterial, antiinflammatory and antitumor activities.1 Isodon wightii (Bentham) H. Hara is a perennial herb commonly distributed in Western Ghats, South India up to 8000 feet. Ent-kaurene diterpenoid, melissoidesin isolated from the leaves showed antioxidant, antiacetylcholinesterase, cytotoxic and anticarcinogenic activities.2-3 In vitro mass multiplication protocol for this important species has also been developed.4 2. Materials and methods 2.1. General 1H (400MHz), 13C(100MHz) (Bruker-400) and 2D NMR (500MHz) spectra including 1H= H correlated spectroscopy (COSY), heteronuclear single quantum coherence (HSQC), heteronuclear multiple bond correlation (HMBC) were recorded in …show more content…
Linoleic acid peroxidation was initiated by the addition of 4 mM FeSO4.7H2O, incubated for 60 min at 37oC and terminated by the addition of 2 mL of ice cold trichloroacetic acid (10% v/v). An amount of 1 mL of thiobarbituric acid (1% w/v in 50 mM NaOH) was added to 1 mL of the reaction mixture, followed by heating at 95oC for 60 min. The reaction sample was read at 532 nm.7 The percentage of linoleic acid peroxidation inhibition activity was calculated using the following equation: % Inhibition = [(AB - AA)/AB] x 100, where AB, absorption of blank sample, AA, absorption of test sample. 2.5.4. Metal chelating activity Briefly, 2 mM FeCl2 was added to different concentrations of test sample and reaction was initiated by the addition of 5 mM ferrozine. The mixture was vigorously shaken and left to stand at room temperature for 10 min. Absorbance was measured at 562 nm after 10 min.8 % Inhibition = [(AB - AA)/AB] x 100, where AB, absorption of blank sample, AA, absorption of test sample. 2.6. Antibacterial