In the present study, we have experimentally and theoretically studied the free-radical quenching property of dihydrocanaric acid (DCA) isolated from seedpods of Holarrhena antidysenterica. A modified method was used to estimate the nitric oxide scavenging effect of the DCA (significant activity of 75.22%) along with methanolic extract of seed pods of Holarrhena antidysenterica (72.80%) compared to the ascorbic acid as standard (40.60%). Studies have also been conducted for superoxide scavenging activity of the DCA (78.82%) and methanolic extract of seed pods (84.28%) compared to quercetin as standard (82.08%). Theoretically, it has been determined by density-functional theory(DFT) calculations using M06-2X hybrid functional and the double-ζ- split-valence 6-31G (d, p) basis set that the nitric oxide scavenging activity of the compound is by the addition of NO radical at double bond position. Predicted biological activity profile of DCA suggests that it has less activity probability (Pa) for toxicity (Pa = 0.730), cytotoxicity (Pa = 0.208), compared to those chemical entities that are already known as anticancer agents indicating that DCA is less toxic and more tolerable for normal cells. Furthermore, molecular docking studies of the DCA with different studied cancer-related receptors [Estrogen receptor (- 60.12 kcal/mol), epidermal growth factor receptor (EGFR) (- 30.33 kcal/mol), estrogen receptor alpha (- 4.82 kcal/mol), uPAR (- 32.55 kcal/mol) and an enzyme having lipid kinase activity phosphoinositide 3-kinase (- 55.94 kcal/mol)] were found to have better binding affinities compared to betulinic acid and doxorubicin. Thus, our findings suggest that the DCA could be a safer and effective alternative in fighting cancer with minimal side effects.

中文翻译：

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二氢卡那酸自由基猝灭活性在癌症治疗中的作用-实验和理论。

在本研究中，我们通过实验和理论研究了从抗痢疾菌种荚中分离出的二氢卡那酸（DCA）的自由基猝灭特性。使用改进的方法来评估 DCA（显着活性为 75.22%）以及抗痢疾霍拉雷纳种荚的甲醇提取物（72.80%）与标准抗坏血酸（40.60%）相比的一氧化氮清除效果。还对 DCA (78.82%) 和种荚甲醇提取物 (84.28%) 的超氧化物清除活性与标准槲皮素 (82.08%) 进行了比较。理论上，采用M06-2X杂化泛函和双δ-分裂价6-31G(d,p)基组通过密度泛函理论(DFT)计算确定该化合物的一氧化氮清除活性为通过在双键位置添加NO基团。DCA 的预测生物活性曲线表明，与已知的抗癌药物化学实体相比，其毒性 (Pa = 0.730)、细胞毒性 (Pa = 0.208) 的活性概率 (Pa) 较低，这表明 DCA 的毒性较小，并且对正常细胞更耐受。此外，DCA与不同研究的癌症相关受体的分子对接研究[雌激素受体（- 60.12 kcal/mol）、表皮生长因子受体（EGFR）（- 30.33 kcal/mol）、雌激素受体α（- 4.82 kcal/mol） ）、uPAR（- 32.55 kcal/mol）和具有脂质激酶活性的酶磷酸肌醇3-激酶（- 55.94 kcal/mol）]被发现与桦木酸和阿霉素相比具有更好的结合亲和力。因此，我们的研究结果表明，DCA 可能是一种更安全、有效的抗癌替代方案，且副作用最小。