Isolation and Enzyme‐Inhibition Studies of the Chemical Constituents from Ajuga bracteosa

Abstract

Bractin A (=(2S,3S,4R,5E)-2-{[(2R)-2-hydroxydodecanoyl]amino}triacont-5-ene-1,3,4-triol; 1) and bractin B (=(2S,3S,4R,5E,8E)-2-{[(2R)-2-hydroxyhexacosanoyl]amino}pentadeca-5,8-diene-3,4,15-triol 1-O-beta-D-glucopyranoside; 2), new sphingolipids, and bractic acid (=(5Z,10Z,15Z)-2-decyl-4,7,8,12,13,17,18-heptahydroxy-20,23-dioxopentacosa-5,10,15-trienoic acid; 3), a long-chain polyhydroxy acid, were isolated from the whole plant Ajuga bracteosa along with four known diterpenoids 4-7. Their structures were deduced by spectral studies including 1D- and 2D-NMR spectroscopy. Compounds 1-3 displayed inhibitory potential against enzyme lipoxygenase, while compounds 4-7 inhibited cholinesterase enzymes in a concentration-dependent manner with IC(50) values in the range 10.0-33.0, 14.0-35.2, and 10.0-19.0 microM for lipoxygenase, acetylcholinesterase, and butyrylcholinesterase, respectively. Lineweaver-Burk, and Dixon plots, and their secondary replots indicated that all compounds exhibit non-competitive type of inhibition with K(i) values in the range of 9.5-35.2, 15.2-36.0, and 11.6-20.5 microM, for lipoxygenase, acetylcholinesterase, and butyrylcholinesterase, respectively.

Evaluation of selected indigenous medicinal plants from the western Himalayas for cytotoxicity and as potential cancer chemopreventive agents

“…Out of the available IC 50 values, the lowest were 0.41µg/mL and 0.44µg/mL for A. bractiosa and S. chirata, respectively (Table 2), which validate the higher potential of these plants as candidates for chemoprevention (Dorai & Aggarwal, 2004, Goodman, 1992. As demonstrated previously (Riaz et al, 2007), components of A. bracteosa also inhibit lipoxygenase activity.…”

Antiarthritic effects of Ajuga bracteosa Wall ex Benth. in acute and chronic models of arthritis in albino rats

“…histamine and serotonin in early phase; kinin-like substances in intermediate phase; and prostaglandins in late phase [11] . Inhibition of turpentine oil-induced joint oedema, suggests the possible effect of EEAB on different phases of inflammation, which in turn could either be due to lipoxygenase and /or cyclooxygenase inhibition as reported previously [6,7] .…”

“…The previous pharmacological investigations on A. bracteosa have reported the antifeedant activity against Spodoptera littoralis larvae [2] , cancer chemopreventive [3] , and antiplasmodial [4,5] activities. A. bracteosa was also reported to inhibit the acetylcholinesterase, butyrylcholinesterase and lipoxygenase activity [6] .…”

Evaluation of <i>in vitro</i> and <i>in vivo</i> anti-arthritic potential of <i>Berberis calliobotrys</i>

“…The acute inflammatory response in the knee joint of rat stimulated by turpentine oil was reduced in a dose-dependent approach by oral administration of B. calliobotrys at 50, 100 and 200 mg/kg (Table II). The doable inhibitory effect of B. calliobotrys on different phases of inflammation elicited in turpentine oil-induced joint edema might be due to inhibition of either lipoxygenase or cyclooxygenase enzymes (Riaz et al, 2007;Gautam et al, 2011). Formaldehyde induced arthritis is one of most commonly used acute non-immunological arthritis model for investigating the anti-arthritic potential and anti-proliferative activity of a plant extract (Greenwald, 1991).…”