In vitro evaluation of the antidiabetic properties of a traditional Sooranam polyherbal ethanolic extract

INTRODUCTION

Type II diabetes mellitus stands as a predominant metabolic disorder of contemporary clinical concern.^[1] Diabetes affected over 537 million people worldwide in 2021, with prevalence rising rapidly and healthcare costs reaching nearly $1 trillion annually.^[2] Despite this, almost half of those with diabetes remain undiagnosed, particularly in low- and middle-income countries, heightening the risk of serious complications such as cardiovascular disease and kidney failure. Persistent hyperglycemia drives the development of microvascular complications such as nephropathy, neuropathy, and retinopathy through mechanisms involving oxidative stress, chronic inflammation, and the accumulation of advanced glycation end products, significantly worsening patient outcomes and straining healthcare resources.^[3,4] Although conventional treatments such as insulin and oral hypoglycemic agents such as metformin and sulfonylureas effectively manage blood glucose levels, they are frequently accompanied by side effects ranging from gastrointestinal disturbances to liver toxicity. This underscores the urgent need for safer and more effective alternative therapies.^[5,6] India’s rich heritage of ethnomedicine offers a vast repository of medicinal plants traditionally utilized to alleviate diabetic conditions with minimal adverse effects.^[7] Various phytochemicals, including flavonoids, alkaloids, terpenoids, and polyphenols, have been identified as responsible for the antidiabetic properties of several botanical species.^[8,9] The Kolli Hills region, located in Tamil Nadu’s Namakkal district, is renowned for its diverse flora and rich tribal knowledge pertaining to herbal remedies. The indigenous communities of Kolli Hills extensively rely on native medicinal plants for primary healthcare, including diabetes management.^[9-11] Scientific evidence supporting traditional polyherbal antidiabetic remedies remains limited. Sooranam, a polyherbal ethanolic extract traditionally used in Kolli Hills for diabetes management, warrants systematic evaluation. This study investigates its antidiabetic potential using in vitro assays targeting key mechanism such as inhibition of carbohydrate-hydrolyzing enzymes and enhancement of cellular glucose uptake. By generating empirical data, the study aims to validate ethnopharmacological claims and support the development of plant-based therapeutic options that may complement conventional diabetes treatment.

MATERIALS AND METHODS

RESULTS

The ethanol extract of Sooranam (15PC) was subjected to preliminary phytochemical evaluation, which confirmed the presence of flavonoids, phenolics, tannins, alkaloids, and saponins, while steroids were absent, indicating a rich profile of bioactive constituents commonly associated with antihyperglycemic activity. The extract exhibited significant inhibitory activity against both α-amylase and α-glucosidase in a dose-dependent manner. In the α-amylase inhibition assay, the extract produced 10.69%, 54.70%, 76.99%, 88.06%, 90.32%, and 91.56% inhibition at concentrations of 10, 20, 40, 80, 160, and 320 µg/mL, respectively, with an IC₅₀ value of 23.70 µg/mL, whereas the standard Acarbose showed stronger activity with an IC₅₀ of 10.84 µg/mL [Figure 1].

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Figure 1:

The image illustrates the concentration-dependent inhibitory effect of the 15PC extract compared with the standard on α-amylase activity.

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A similar trend was observed in the α-glucosidase assay, where inhibition increased steadily from 7.99% at 10 µg/mL to 92.67% at 320 µg/mL, closely approximating Voglibose, which showed 95.76% inhibition at the same concentration, although the standard remained more potent at lower levels, the extract’s inhibitory capacity became nearly comparable beyond 80 µg/mL [Figure 2]. Complementing its enzyme-inhibitory potential, the 15PC extract demonstrated strong glucose-uptake–enhancing activity in the yeast cell model, showing a concentration-dependent increase from 42.8% uptake at 0.5 mg/mL to 56.3% at 1 mg/mL, 68.4% at 2 mg/mL, and reaching a maximum of 81.7% at 5 mg/mL, indicating substantial reduction of extracellular glucose and suggesting improved transport across the yeast membrane [Figure 3]. Collectively, the extract exhibited robust antidiabetic activity across all in vitro models, with inhibitory effects on key carbohydrate-digesting enzymes and significant enhancement of glucose utilization, demonstrating a multifaceted mechanism supported by its rich phytochemical profile.

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Figure 2:

This image displays the inhibitory activity of the 15PC extract and the standard drug Voglibose on α-glucosidase across increasing concentrations.

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Figure 3:

This image displays the inhibitory activity of the 15PC extract and the standard drug Voglibose on α-glucosidase across increasing concentrations.

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DISCUSSION

The ethanolic extract of Sooranam was analyzed for its phytochemical constituents to gain preliminary insight into its therapeutic potential. Qualitative screening confirmed the presence of alkaloids, flavonoids, phenolics, tannins, and saponins, while steroids were absent. These phytochemicals are noteworthy since they are frequently associated with antidiabetic mechanisms, such as the inhibition of carbohydrate-digesting enzymes, antioxidant protection, and enhancement of glucose utilization. The detected abundance of these compounds supports earlier findings that link the antidiabetic potential of medicinal plants to their ability to regulate glucose metabolism and alleviate oxidative stress-induced cellular damage.^[16,17] Flavonoids and phenolic compounds, in particular, are known to act as antioxidants that can protect pancreatic β-cells from oxidative damage, enhance insulin secretion, and inhibit carbohydrate-hydrolyzing enzymes.^[17,18] Despite being less potent than the standard, the extract showed relevant inhibitory action, suggesting a moderating effect on starch digestion. The α-glucosidase inhibition assay was then conducted to assess the extract’s impact on the final step of carbohydrate digestion. The moderate IC₅₀ values observed for α-amylase (23.70 µg/mL) and α-glucosidase (40.75 µg/mL) inhibition suggest a physiological benefit comparable to other plant-based enzyme inhibitors such as Psiadia punctulata, Meriandra bengalensis, and Quercus coccifera, which also displayed dose-dependent enzyme inhibition in vitro.^[18,19] Similar results were observed with ethanolic extracts of the Ayurvedic polyherbal formulation Shirishadi, where IC₅₀ values for α-amylase and α-glucosidase were 0.68 and 2.89 mg/mL, respectively, confirming the ethnomedicinal rationale for using polyherbal formulations that target multiple carbohydrate-processing enzymes.^[20]

Beyond enzyme inhibition, the extract showed strong glucose-uptake-enhancing activity in the yeast cell model. Glucose uptake increased steadily from 42.8% at 0.5 mg/mL to 81.7% at 5 mg/mL, demonstrating a marked dose-dependent improvement in cellular glucose transport. This enhancement indicates that the extract not only reduces glucose liberation during digestion but also facilitates intracellular glucose utilization, suggesting possible insulin-mimetic or insulin-sensitizing effects. Such combined actions are comparable to multitargeted antidiabetic mechanisms described for Q. coccifera and T. cordifolia, which exert simultaneous effects on enzymatic pathways and cellular glucose uptake.^[19,21] The observed ability of the extract to lower extracellular glucose without apparent cytotoxicity aligns with previous reports that plant-based therapies can modulate glycemic parameters more gently than synthetic drugs, which often present greater gastrointestinal adverse effects.

Collectively, the phytochemical richness of the Sooranam extract appears to underpin its multi-targeted antidiabetic activity, encompassing inhibition of α-amylase and α-glucosidase as well as significant enhancement of glucose uptake. Although the extract is less potent than standard pharmaceutical agents on an IC₅₀ basis, its combined enzymatic and cellular effects represent a meaningful therapeutic potential. These findings support the traditional use of polyherbal formulations in glycemic management and justify further investigations, including mechanistic studies, in vivo evaluations, and characterization of individual bioactive molecules responsible for the observed effects.

CONCLUSION

The ethanolic extract of Sooranam, a traditional polyherbal formulation from Kolli Hills, displayed significant in vitro antidiabetic activity by acting through multiple complementary mechanisms. Inhibition of both α-amylase and α-glucosidase occurred in a dose-dependent manner, while the extract also enhanced glucose uptake in the yeast cell model, suggesting an ability to modulate postprandial glucose metabolism as well as cellular glucose utilization. These effects are likely driven by its rich content of bioactive phytochemicals, such as flavonoids, phenolics, tannins, and alkaloids. Although the potency observed was lower than that of standard antidiabetic agents, the extract’s broad-spectrum and multi-target actions highlight its potential as a natural adjunct in diabetes care. These findings offer scientific support for the ethnomedicinal application of Sooranam in diabetes management and point to the need for further studies on bioactive compound isolation, mechanistic elucidation, and in vivo validation to realize its therapeutic promise. This extract may serve as a complementary therapeutic for early-stage diabetes.