Exploring the therapeutic potential of <i>Leea rubra</i> (Vitaceae): Antioxidant efficacy, brine shrimp lethality, and <i>in vivo</i> anticancer activity against EAC cells in Swiss albino mice

<i>Leea</i> species are traditionally used to treat cancer, while <i>Leea rubra</i> leaves (LRL) aid fever, stomach ache, rheumatism, arthritis, intestinal diseases, etc. This study explores the polyphenolic contents, antioxidant, and anticancer potential of LRL. <i>In vitro</i> standard methods were used for the evaluation of the polyphenolic contents and antioxidative properties of the methanolic extracts. The anticancer activity was determined by <i>in vitro</i> biological study using Brine Shrimp Nauplii and <i>in vivo</i> standard method using Ehrlich ascites carcinoma (EAC) cell-bearing Swiss Albino mice. The ethyl acetate fraction (EAF) exhibited maximum total antioxidant activity and iron reducing capacity (absorbance 0.192 ± 0.010 and 3.003 ± 0.02 at concentrations of 25μg/ml, respectively) and the highest DPPH and hydroxyl radical scavenging activity (IC₅₀ 5.29 and 17.34 μg/ml, respectively) among the fractions. The phenolic and flavonoid contents of EAF were also found to be higher than other fractions. EAF showed the highest brine shrimp lethality with LC₅₀ 28.64 μg/ml. The tumor cell growth inhibition (71.3%) in mice by EAF was significant (<i>p</i>&lt;0.001). The findings indicate that the EAF of LRL is a good source of antioxidants and possesses strong cytotoxic and anticancer activity.