Tulsi: benefits, dosage, contraindications

Adaptogen

Tulsi, recognized for its adaptogenic properties, helps regulate stress and fatigue. It works by normalizing physiological and biochemical changes related to stress, such as lipid peroxidation and lactic acid levels, thanks to active compounds like ocimumosides A and B. These compounds favorably influence monoaminergic systems by modulating the activity of neurotransmitters such as norepinephrine, adrenaline, dopamine, and serotonin, contributing to better stress and anxiety management. Studies show that tulsi can improve resistance to chronic stress and fatigue by also adjusting immune responses and reducing oxidation, while normalizing corticosterone levels. These effects are comparable to those of conventional antistress and antioxidant drugs, demonstrating the potential efficacy of tulsi in various therapeutic contexts.

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Anti-inflammatory

Tulsi is recognized for its anti-inflammatory properties both in acute and chronic inflammation models in animals. Several forms of tulsi extract, such as fresh leaves, essential oil, and ethanolic extracts of leaf tissues, show significant anti-inflammatory effects. These effects are attributed to components like eugenol and linoleic acid, which inhibit the arachidonate metabolic pathways involving cyclooxygenase and lipoxygenase enzymes. These components also reduce leukocyte migration and vascular permeability, comparable to the effects of non-steroidal anti-inflammatory drugs like ibuprofen and aspirin.

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Antioxidant

The antioxidant properties of tulsi are mainly due to the presence of phenolic compounds, such as eugenol, luteolin, and apigenin. These antioxidants effectively combat free radicals, protecting against lipid peroxidation and increasing internal antioxidant defenses such as glutathione and various enzymes like superoxide dismutase and catalase. Tulsi extracts have also shown their ability to reduce oxidative damage in various stress models, thus supporting their protective role in the prevention of neurodegenerative and heart diseases. It is noteworthy that red tulsi has a higher antioxidant content than white tulsi.

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Anxiolytic

Tulsi is studied for its anxiolytic effects comparable to those of conventional drugs, thanks to the ursolic acid present in its leaves. In animal models of depression, tulsi demonstrated antidepressant activities similar to imipramine, a reference in antidepressants. Tulsi extracts also act on dopaminergic neurons, which might explain their ability to improve mood and reduce depression. A study in humans showed that administering 500 mg of tulsi twice a day significantly alleviated symptoms of general anxiety, as well as associated stress and depression, in psychiatric patients.

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Hepato-protective

Tulsi extracts show protective effects against various toxic substances in numerous in vitro and in vivo models. These hepatoprotective effects are mainly attributed to tulsi's antioxidant capacity. Aqueous extracts of tulsi significantly reduce lipid peroxidation and modulate levels of enzymatic and non-enzymatic antioxidants affected by toxic compounds like butylparaben. Tulsi also helps restore endocrine and histopathological imbalances induced by common pesticides and protects against the toxicity of various chemicals, including drugs like paracetamol. It enhances liver protection, notably when used in combination with silymarin, another natural hepatoprotective agent.

Anticancer

Tulsi's anticancer properties are mainly attributed to its antioxidant effects and its ability to modulate detoxification enzymes. Studies have shown that tulsi can reduce the incidence of neoplasms and carcinomas in various animal models by increasing the activity of enzymes that detoxify carcinogens, such as cytochrome P450 and glutathione S-transferase. Furthermore, tulsi can reduce lipid peroxidation and elevate glutathione levels, thus contributing to the protection against genetic damage and oxidation. Tulsi also acts by inhibiting proliferative activity and inducing apoptosis in cancer cells. Finally, in vitro studies have demonstrated that tulsi leaf extracts can reduce the formation of DMBA-DNA adduct (chemical compound binding to DNA) in rat hepatocytes, which is an indicator of reduced carcinogenic potential.

Hormonal metabolism

Tulsi leaf extract has shown effects on glycemic control, thyroid function, and androgen production. Preliminary studies in animals and humans suggest that tulsi leaf extract possesses hypoglycemic activity, improving beta-cell function and stimulating insulin secretion. It also appears that tulsi increases the activity of enzymes essential to carbohydrate metabolism. Regarding the thyroid, a high dose of this extract decreased thyroxine (T4) concentrations without affecting triiodothyronine (T3) levels or the T3/T4 ratio. Additionally, research on animals indicates that tulsi could reduce sperm quantity and motility, influencing fertility, although these parameters return to normal two weeks after stopping the treatment.

Cardiovascular

Tulsi exerts beneficial effects on cardiovascular health in various ways. Tulsi seed oil prolongs bleeding time, likely due to its inhibitory action on platelet aggregation. This activity is attributed to the linolenic acid in the oil, which can be converted into eicosapentaenoic acid (EPA). EPA has the capacity to inhibit thromboxane A2, thereby reducing platelet aggregation and potentially promoting better blood fluidity. Furthermore, tulsi seed oil may also have a blood pressure-lowering effect, attributed to its vasodilatory effects observed in animal models. These properties suggest that tulsi could play a beneficial role in managing blood pressure and preventing cardiac complications associated with hypertension and excessive platelet aggregation.

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Immuno-modulator

Tulsi seed oil shows a notable ability to modulate both humoral and cellular immunity. In animals, it enhances immune responses by improving antibody production and reducing histamine release from mast cells, indicating a positive impact on humoral immune responses. The immunomodulatory effects of tulsi are also observed in humans. A controlled study demonstrated that ethanolic extract of tulsi leaves significantly increases important cytokine levels such as interferon-γ and interleukin-4, as well as helper T cells and NK cells.a0

Cognitive function

Tulsi, also known as holy basil, shows a notable ability to improve cognition. In Alzheimer's disease models in rats, it enhances reference memory, working memory, spatial learning, and antioxidant activity. Tulsi extracts have also demonstrated beneficial effects on memory improvement in stressed rats that exhibit memory deficits. They reduce acetylcholinesterase activity, which is beneficial for enhancing passive memory tasks. In a mouse experiment, tulsi showed anti-amnesiac effects, helping to mitigate the amnesic effects of scopolamine and memory deficits induced by aging.

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