A Review of Pharmacological Evaluation of Karunjeeragam (Nigella sativa) in the Regulation of Menstrual Cycles: A Siddha Perspective on Soothaga Vayu and Hormonal Homeostasis

Abstract Background: In Siddha medicine, Karunjeeragam (Black Cumin) is revered as a potent Karppasaya Suddhi (uterine cleanser) and Uthirandakari (emmenagogue). Menstrual irregularities, particularly oligomenorrhea and secondary amenorrhea, are traditionally attributed to the vitiation of Vatham and the resulting stagnation of Abaana Vayu. Karunjeeragam is frequently prescribed to restore the rhythmic shedding of the endometrium by correcting this humoral imbalance. Objective: This review aims to analyze the therapeutic role of Karunjeeragam in regulating menstruation, focusing on its ability to pacify Vata-Kapha and its modern pharmacological correlation with endocrine modulation. Methodology: Data were synthesized from classical Siddha texts, including Pathartha Guna Chinthamani and Agathiyar Gunavagadam, alongside modern pharmacological studies investigating the effects of Thymoquinone (the active principle of Nigella sativa) on the hypothalamic-pituitary-ovarian (HPO) axis. Results: Siddha literature classifies Karunjeeragam as having Ushna Veeryam (Hot Potency) and Karppu Suvai (Pungent Taste), which effectively eliminates "cold" obstructions in the uterus. Modern research corroborates these claims, demonstrating that Nigella sativa possesses estrogenic properties and improves ovarian follicular development. Its volatile oils exert an antispasmodic effect on the uterine smooth muscles, facilitating a regulated and pain-free menstrual flow. Furthermore, its ability to improve insulin sensitivity makes it particularly effective for menstrual regulation in cases of Polycystic Ovary Syndrome (PCOS). Conclusion: Karunjeeragam serves as a dual-action agent in Siddha gynecology: it acts as a physical stimulant for menstrual onset while simultaneously balancing the subtle Vayu responsible for reproductive health. It is a vital component in the management of menstrual disorders, offering a natural alternative to synthetic hormonal therapy.