R.D. Lele

Chief Physician & Director, Nuclear Medicine Dept. Jaslok Hospital & Research Centre, India

Abstract:

Osmotin, a recently discovered PR-5 (pathogenesis related family of protein 5) plant analogue of adiponectin, and acts through adiponectin receptors (Narasimhan LM et al. 2005).

Adiponectin and osmotin act via AdipoR1 receptors in muscle and adipoR2 receptors in liver, and act as insulin sensitizers and regulators of energy homeostasis via AMPK activation (Wolf G 2003) Fig. 1.

Ancient Indian System of Medicine Ayurveda describes 3 kinds of diet – “ahar”- “satwik”, “Rajasik” and “Tamasik”. The sages (Rishis) took satwik ahar consisting of “Kanda, Moola, Phala” (vegetables and fruits) and lived for 100 years. In today’s parlence this represents a 1300 calorie diet (which causes the least oxidative stress), high fibre, low fat, low sodium, high potassium and minerals and plenty of anti-oxidants. I suggest that part of the beneficial effect of fruits and vegetables is due to their osmotin content which remains stable in the diagestive tract (Lele RD 2012).

Trivedi VR et al. (2012) isolated osmotin from salt-adapted tobacco leaves cell suspension and showed their efficacy in male Wistar rats  (given two weeks of atherogenic diet ) (CCT) for day 1- 14 to produce Hypercholesterolemia and atherosclerosis. From day 15 to 28 they were given treatment with osmotin I (5 mg/kg iv) and osmotin II (5 mg/kg iv) and compared with atorvastatin (5 mg/kg po). Both osmotin I & II produced decrease in body weight, Serum Triglyceride and total cholesterol, C-reactive protein (CRP) and decrease in atherosclerotic lesions area in the abdominal aorta. These effects were comparable to those produced by atorvastatin.

Hypoadiponectinemia is a feature of insulin resistance and metabolic syndrome (visceral obesity hypertension, atherosclerosis and T2DM). Upregulation of adiponectin by Thiazolodine drug is a new therapeutic strategy. T2DM increase adiponectin and decrease TNFα. Osmotin will be as effective as adiponectin as an insulin-sensitizer. Our current efforts are to estimate the osmotin content of fruits (such as apples) and vegetables and introduce osmotin as a therapeutic agent in insulin resistance and metabolic syndrome.