Ocimum Sanctum and Blood Glucose
Ocimum sanctum, commonly known as holy basil or tulsi, is an aromatic perennial plant in the family Lamiaceae. It is native to tropical and subtropical regions of Australia, Malesia, Asia, and the western Pacific. Tulsi is cultivated for religious and traditional medicine purposes, and also for its essential oil. Ocimum sanctum has many health benefits, including its hypoglycemic effects.
Researchers studied the effects of oil from Ocimum sanctum leaves on diabetic rats. They found that the oil, primarily containing α-linolenic acid, lowered blood glucose and improved lipid profiles. At the end of the 3 weeks of treatment, the blood glucose level was ~200 mg/dL in the diabetic rats treated with Ocimum sanctum compared to that of untreated diabetic rats (~250 mg/dL), a 25% reduction. Compared to the untreated diabetic rats, the lipid profile improved with Ocimum sanctum treatment improved lipid profile, the total cholesterol and triglyceride levels in the treated diabetic rats were 70±4 and 45±8 mg/dL, which were significantly lower than those in the untreated diabetic rats with 93±7 and 92±7 mg/dL, respectively (1).
Ocimum sanctum also protected the kidneys from oxidative stress, while not significantly affecting the liver and heart. The average dried Ocimum sanctum leaf powder consumption of the rats in the treatment group was 4.45 g/kg/day. The daily dose of Ocimum sanctum fixed oil administered in this study was ~46.54 mg/kg/day. The study suggested that Ocimum sanctum leaf oil had anti-diabetic and kidney-protective effects, possibly due to α-linolenic acid, which was the main fatty acid component of the oil (1).
Tulsi extract at a dose of 200 mg per kg of body weight was given to diabetic rats through their diet for eight weeks. The results showed significant improvements, including reduced blood glucose, better lipid profile, and enhanced glucose tolerance. At baseline and the end of 8 weeks of treatment, the blood glucose levels in the normal control rats were 93.4±24.3 and 83.0±24.2 mg/dL, in the untreated diabetic rats were 165.6±50.2 and 300.5±50.7 mg/dL, and in the diabetic rats treated with Tulsi extract were 172.5±6.43 and 112.0±7.2 (-35% from baseline) mg/dL, respectively. The extract also demonstrated antioxidant properties by decreasing lipid peroxidation and increasing levels of antioxidant enzymes in various organs (2).
Researchers tested if giving rats Ocimum sanctum extract orally could protect them from insulin resistance caused by a fructose diet. Male Wister rats were divided into four groups: starch diet, fructose diet, fructose diet with Ocimum sanctum extract, and starch diet with Ocimum sanctum extract. Over 60 days, they tracked body weight, glucose, insulin, and triglycerides every 15 days. Ocimum sanctum had no impact on rats with a starch diet, but in those with a fructose diet, there was weight gain, high glucose, insulin, triglycerides, and insulin resistance. The group on fructose showed increased glucose and insulin levels over time, but when given Ocimum sanctum extract, these increases were prevented or reduced (3).
The fructose-fed group showed a gradual increase in plasma glucose levels during the experimental period, having significantly higher glucose levels at 30 days (93.05 ± 1.6), 45 days (94 ± 3.9), and 60 days (103 ± 2.2) mg/dL with 14, 15, and 25 % rise when compared with the starch-fed group. Feeding Ocimum sanctum extract at 200 mg/kg per day prevented the glucose level increases. The fructose-fed group also showed a gradual increase in plasma insulin during the experimental period, having significantly higher concentrations of insulin at 30 days (61.48± 1.0), 45 days (98.19 ± 1.6), and 60 days (139.4± 3.5) mcIU/ml with 40, 112, and 178 % increase, respectively, when compared with the starch group. The plasma insulin concentrations of fructose + Ocimum sanctum were 48.55 ± 0.37, 52.7 ± 0.45, and 70.4 ± 0.72 mcIU/ml at 30, 45, and 60 days, respectively, with 21, 46, and 49 % lower levels when compared with the fructose group (3).
Feeding rabbits a diet with fresh tulsi leaves (2 gm/kg body weight) for 30 days significantly lowered their blood glucose levels. At baseline and the end of 30 days, the blood glucose levels were 150.55±17.94 and 151.07±17.86 for the control group, and 148.80±19.02 and 110.0±17.25 (-26%) for the treatment group, respectively. The intake of Ocimum sanctum also increased levels of antioxidants and reduced lipid peroxidation compared to the control group. The leaves demonstrated the ability to neutralize free radicals. These findings confirm that Ocimum sanctum leaves are effective in reducing blood glucose levels, with their antioxidant properties playing a key role in this hypoglycemic effect (4).
The effects of treatment with holy basil leaves on fasting and postprandial blood glucose and serum cholesterol levels in humans were examined through a randomized, placebo-controlled, crossover single-blind trial. Results indicated a significant decrease in fasting and postprandial blood glucose levels during treatment with holy basil leaves compared to treatment with placebo. Fasting blood glucose fell by 21.0 mg/dL, with a confidence interval of difference -31.4 - (-)11.2 (p < 0.001), and postprandial blood glucose fell by 15.8 mg/dL, with a confidence interval of -27.0 - (-)5.6 (p < 0.02). The lower values of glucose represented reductions of 17.6% and 7.3% in the levels of fasting and postprandial blood glucose, respectively. Urine glucose levels showed a similar trend. Mean total cholesterol levels showed mild reduction during the basil treatment period. These findings suggested that basil leaves could be prescribed as an adjunct to dietary therapy and drug treatment for mild to moderate diabetes (5).
These studies showed that Ocimum sanctum extract could prevent hyperglycemia, hypertriglyceridemia, hyperinsulinemia, and can improve insulin resistance in animal models, and lower blood glucose in people with diabetes. Basil leaves might delay insulin resistance development and could be a supportive therapy for diabetic patients with insulin resistance.
Reference:
1. Suanarunsawat T, Anantasomboon G, Piewbang C. Anti-diabetic and anti-oxidative activity of fixed oil extracted from Ocimum sanctum L. leaves in diabetic rats. Exp Ther Med. 2016 Mar;11(3):832-840. doi: 10.3892/etm.2016.2991. Epub 2016 Jan 13. PMID: 26998000; PMCID: PMC4774317.
2. Hussain EH, Jamil K, Rao M. Hypoglycaemic, hypolipidemic and antioxidant properties of tulsi (Ocimum sanctum linn) on streptozotocin induced diabetes in rats. Indian J Clin Biochem. 2001 Jul;16(2):190-4. doi: 10.1007/BF02864859. PMID: 23105316; PMCID: PMC3453628.
3. Reddy SS, Karuna R, Baskar R, Saralakumari D. Prevention of insulin resistance by ingesting aqueous extract of Ocimum sanctum to fructose-fed rats. Horm Metab Res. 2008 Jan;40(1):44-9. doi: 10.1055/s-2007-993218. Epub 2007 Dec 18. PMID: 18085503.
4. Sethi J, Sood S, Seth S, Talwar A. Evaluation of hypoglycemic and antioxidant effect ofOcimum sanctum. Indian J Clin Biochem. 2004 Jul;19(2):152-5. doi: 10.1007/BF02894276. PMID: 23105475; PMCID: PMC3454204.
5. Agrawal P, Rai V, Singh RB. Randomized placebo-controlled, single blind trial of holy basil leaves in patients with noninsulin-dependent diabetes mellitus. Int J Clin Pharmacol Ther. 1996 Sep;34(9):406-9. PMID: 8880292.
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