Antihypertensive Activity of Stevia rebaudiana Bertoni (Bertoni) Nitish. K.Raghav*, Department of Pharmacognosy, Faculty
of Pharmacy, S.B.S. College of Pharmacy Patti. Amritsar 143001. India ABSTRACT Stevia rebaudiana Bertoni (Bertoni) commonly known as Sweetleaf is an incredibly sweet herb, obtained by a natural selective breeding process of the sweetest Stevia parent plants. The literature survey reveals that the leaves have been used as a folkfore medicine as sweetening agent , antibacterial, anti fungal, anti- inflammatory, anti-microbial, anti-viral, anti-yeast, cardiotonic, diuretic, hypoglycemic and hence a boon to diabetic people, hypotensive, tonic, and vasodilator. Stevia leaves are about 5 cm long and 2 cm wide and are planted crosswise, facing each other. In the wild, the height of the plant varies from 40 to 80 cm but when cultivated, the Stevia can become 1 metre high. Stevia can be grown on relatively poor soil. The plants can be used for commercial production for 6 years, during which five times a year a harvest takes place of the part of the plant that is above the ground. The roots remain in place and so the plant regenerates again. Plants, which are 1 metre high, have a dry weight of 70 g on average. The dry weight of the leaves can vary from 15 to 35 g per plant. Animal and human studies have suggested that
stevioside has an antihypertensive effect. This study was undertaken to investigate the long-term (2-year) efficacy and tolerability of stevioside in patients with mild essential hypertension. Secondary objectives were to determine the effects of stevioside on left ventricular mass index (LVMI) and quality of life (QOL). Stevioside powder (approved by India PFA 1073) was obtained from ASR Herbals. METHODS: This was a multicenter, randomized, double-blind, placebo-controlled trial in men and women aged between 20 and 75 years with mild essential hypertension (systolic blood pressure
140-159 mm Hg and diastolic blood pressure 90-99 mm Hg). Patients took capsules containing 500 mg stevioside powder or placebo 3 times daily for 2 years. Blood pressure was measured at monthly clinic visits; patients were also encouraged to monitor blood pressure at home using an automated device. LVMI was determined by 2-dimensional echocardiography at baseline and after 1 and 2 years of treatment. QOL was assessed using the Medical Outcomes Study. Electrocardiographic, laboratory, and QOL parameters were assessed at the beginning of treatment, and at 6 months, 1 year, and 2 years. RESULTS: One hundred seventy-four patients (87 men, 87 women) were enrolled in the study, and 168 completed it: 82 (42 men, 40 women; mean age, 52 <5> years) in the stevioside group and 86 (44 women, 42 men; mean age, 53 <6> years) in the placebo group. After 2 years, the stevioside group had significant decreases in mean (SD) SBP and DBP compared with baseline (SBP, from 150 <7.3> to 140 <6.8> mm Hg; DBP, from 95 <4.2> to 89 <3.2> mm Hg; P < 0.05) and compared with placebo (P < .05). Based on patients'' records of self-monitored blood pressure, these effects were noted beginning approximately 1 week after the start of treatment and persisted throughout the study. There were no significant changes in body mass index or blood biochemistry, and the results of laboratory tests were similar in the 2 groups throughout the study. No significant difference in the incidence of adverse effects was noted between groups, and QOL scores were significantly improved overall with stevioside compared with placebo (P < 0.001). Neither group had a significant change in mean LVMI. However, after 2 years, 6 of 52 patients (11.5%) in the stevioside group had left ventricular hypertrophy (LVH), compared with 17 of 50 patients (34.0%) in the placebo group (P < 0.001). Of tose who did not have LVH at baseline, 3 of 46 patients (6.5%) in the stevioside group had developed LVH after 2 years, compared with 9 of 37 patients (24%) in the placebo group (P < 0.001). CONCLUSIONS: In this 2-year study in patients with mild hypertension, oral stevioside significantly decreased SBP and DBP compared with placebo. QOL was improved, and no significant adverse effects were noted. Correspondence at: Nitish Raghav E-mail: nk_raghav@yahoo.co.in