Phytochemical Profile, Antidiabetic Mechanisms, and Meta- Analytic Evidence of Costus igneus: A PRISMA-Compliant Systematic Review

Background: Costus igneus, commonly known as the insulin plant, is a perennial medicinal herb belonging to the family Costaceae and is traditionally used for glycemic control. Its ethnomedicinal use in Ayurveda involves daily consumption of fresh leaves to regulate blood glucose levels. Phytochemical investigations have identified diverse bioactive compounds, including flavonoids, triterpenoids, phenolic compounds, alkaloids, glycosides, and steroids, which are associated with antidiabetic, antioxidant, and anti-inflammatory activities. Objective: This systematic review and meta-analysis aimed to evaluate the phytochemical composition and pharmacological effects of Costus igneus, with particular emphasis on triterpenoids and their mechanistic role in glycemic regulation and disease management. Methods: A systematic literature search was conducted using PubMed, Scopus, Web of Science, ScienceDirect, Google Scholar, and Wiley Online Library for studies published between January 2000 and December 2025. The review was performed in accordance with PRISMA-2020 guidelines. A total of 32 records were identified, of which 14 studies met the inclusion criteria and were included in qualitative synthesis. Quantitative outcome data from experimental studies were analyzed using meta-analytic methods. A comprehensive literature search was conducted across multiple electronic databases including PubMed, Scopus, Web of Science, ScienceDirect, Google Scholar, and Wiley Online Library to identify relevant studies published between January 2000 and December 2025. The search strategy employed combinations of controlled vocabulary and keyword terms including “Costus igneus,” “insulin plant,” “Costus igneus phytochemicals,” “triterpenoids,” “corosolic acid,” “lupeol,” “diosgenin,” “flavonoids,” “phenolic compounds,” “antidiabetic activity,” “antioxidant activity,” and “pharmacological activity.” Boolean operators AND and OR were used to combine search terms and maximize retrieval of relevant studies. Reference lists of included articles were also manually screened to identify additional eligible studies. Results: Phytochemical analysis confirmed the presence of triterpenoids, flavonoids, phenolics, and glycosides with demonstrated antioxidant and antihyperglycemic properties. Meta-analysis revealed a significant reduction in fasting blood glucose following Costus igneus treatment compared with diabetic control (pooled mean difference −31.24 mg/dL; 95% CI −32.26 to −30.21). The mechanisms of action include enhanced insulin secretion, improved peripheral glucose uptake, inhibition of carbohydratedigesting enzymes, and protection of pancreatic β-cells from oxidative damage. Conclusion: Costus igneus exhibits significant antidiabetic potential through multiple pharmacological mechanisms. While preclinical evidence is promising, further clinical studies and standardized phytochemical investigations are required to establish its therapeutic efficacy and clinical applicability.