Abstract

PHYTOCHEMICAL SCREENING OF METHANOLIC EXTRACTS OF INDIGENOUS MEDICINAL PLANT SMILAX CHINA

Md. Ahsan Habib, Md. Abdul Mannan*, Md. Shifat Hossain, Mohammad Abu Bin Nyeem, Mahamudul Hasan Bhuiyan, Muhammad Yeasin Arafat, Md. Wasif Iqbal

Abstract

Smilax china L. is an indigenous medicinal plant widely recognized for its therapeutic value in traditional systems of medicine across Asia. The plant has long been used for the treatment of inflammatory disorders, skin diseases, rheumatism, urinary tract infections, diabetes, and various microbial infections owing to its rich phytochemical composition. The growing interest in plant-derived bioactive compounds has encouraged extensive phytochemical investigations to identify secondary metabolites that may contribute to the pharmacological properties of medicinal plants. Methanol is considered one of the most effective extraction solvents because of its ability to dissolve a wide range of polar and moderately polar phytoconstituents, making it suitable for qualitative phytochemical screening. Therefore, the present study was undertaken to qualitatively evaluate the phytochemical constituents present in the methanolic extract of the indigenous medicinal plant Smilax china. The methanolic extract of Smilax china was subjected to standard qualitative phytochemical screening using established chemical tests for the detection of major classes of secondary metabolites. Alkaloids were detected using Mayer's, Wagner's, Dragendorff's, and Hager's tests. Carbohydrates were evaluated by Molisch's, Benedict's, and Fehling's tests, while glycosides were identified using Modified Borntrager's and Legal's tests. Saponins were determined by Froth and Foam tests, phytosterols by Salkowski's and Liebermann-Burchard tests, phenolic compounds by the Ferric chloride test, tannins by the Gelatin test, flavonoids by Alkaline reagent and Lead acetate tests, and proteins and amino acids by Xanthoproteic and Ninhydrin tests. The qualitative analysis demonstrated the presence of several important bioactive constituents in the methanolic extract of Smilax china. All alkaloid tests produced positive results, confirming the occurrence of alkaloids in the extract. Similarly, carbohydrates were positively detected by Molisch's, Benedict's, and Fehling's tests. Glycosides were confirmed by both Modified Borntrager's and Legal's tests. The Froth and Foam tests indicated the presence of saponins, while phytosterols were confirmed by positive Salkowski's and Liebermann-Burchard reactions. The Ferric chloride test established the presence of phenolic compounds, whereas flavonoids were successfully detected by both Alkaline reagent and Lead acetate tests. In contrast, tannins were not detected by the Gelatin test, and proteins and amino acids were absent according to both Xanthoproteic and Ninhydrin tests. The phytochemical profile obtained in this investigation agrees with previous reports indicating that Smilax china is particularly rich in steroidal saponins, flavonoids, phenolic compounds, glycosides, and alkaloids, which collectively contribute to its wide range of biological activities. Recent reviews have reported that more than 130 chemical constituents have been identified from Smilax china, with steroidal saponins and flavonoids representing the predominant groups responsible for antioxidant, antimicrobial, anti-inflammatory, antidiabetic, anticancer, antihyperuricemic, and wound-healing activities. Likewise, methanolic extracts have previously been shown to contain numerous phytochemicals with considerable antioxidant potential, supporting the effectiveness of methanol as an extraction solvent. The presence of alkaloids, flavonoids, phenolic compounds, saponins, phytosterols, carbohydrates, and glycosides suggests that the methanolic extract of Smilax china possesses significant therapeutic potential. Many of these phytochemical groups are known to exhibit antioxidant, antimicrobial, anti-inflammatory, immunomodulatory, hepatoprotective, and anticancer properties, either individually or through synergistic interactions. The absence of tannins and proteins in the present study may be attributed to differences in plant origin, harvesting season, extraction procedure, environmental conditions, or genetic variability, as phytochemical composition is known to vary among geographical regions and extraction methods. In conclusion, the present investigation confirms that the methanolic extract of Smilax china contains diverse classes of biologically active phytochemicals that may account for its traditional medicinal applications. The findings provide scientific evidence supporting the ethnomedicinal importance of this indigenous plant and establish a preliminary phytochemical basis for future pharmacological investigations. Further studies involving quantitative phytochemical estimation, chromatographic characterization, toxicity evaluation, and biological activity-guided isolation of active constituents are recommended to identify specific bioactive compounds and facilitate the development of novel plant-based therapeutic agents.

Keywords: Smilax china; Methanolic extract; Phytochemical screening; Indigenous medicinal plant; Alkaloids; Flavonoids; Phenolic compounds; Saponins; Glycosides; Phytosterols.