Recent developments of heterocyclic compounds with indazole moiety as potential antiparasitic agents

Abstract:

Indazole is a vital nitrogen-containing heterocyclic unit in organic and medicinal chemistry research and a helpful precursor molecule for the production of various types of encirclement heterocycles. Indazole analogues are diverse pharmacological agents that can be used to treat a variety of conditions, including cancer, inflammation, infectious diseases, and neurological problems. In fact, the indazole moiety containing inhibitors also showed excellent medicinal properties for the treatment of parasitic diseases. Therefore, the development of new inhibitors has immense promise for usage as key components for the next generation as antiparasitic medication. In this review, we have summarized the recent developments of indazole-containing antiparasitic inhibitors, specially anti-protozoal, anti-fungal, and antiamoebic inhibitors, as well as their structure-activity relationship (SAR) findings for medicinal chemists who are searching for new preclinical parasitic drug candidates.

A Novel Tetraenoic Fatty Acid Isolated from Amaranthus spinosus Inhibits Proliferation and Induces Apoptosis of Human Liver Cancer Cells

Amaranthus spinosus Linn. (Family: Amaranthaceae) has been shown to be useful in preventing and mitigating adverse pathophysiological conditions and complex diseases. However, only limited information is available on the anticancer potential of this plant. In this study, we examined the antiproliferative and pro-apoptotic effects of a novel fatty acid isolated from A. spinosus-(14E,18E,22E,26E)-methyl nonacosa-14,18,22,26 tetraenoate-against HepG2 human liver cancer cells. We used 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay to determine cell viability, flow cytometry assay for cell cycle analysis, and Western blot analysis to measure protein expression of Cdc2), cyclin B1, Bcl-2-associated X protein (Bax), and B-cell lymphoma 2 (Bcl-2). The MTT assay showed that the fatty acid markedly inhibited the proliferation of HepG2 cells in a dosage-dependent fashion, with a half maximal inhibitory concentration (IC50) value of 25.52 µmol/L. This antiproliferative result was superior to that of another known fatty acid, linoleic acid (IC50 38.65 µmol/L), but comparable to that of standard anticancer drug doxorubicin (IC50 24.68 µmol/L). The novel fatty acid also induced apoptosis mediated by downregulation of cyclin B1, upregulation of Bax, and downregulation of Bcl-2, resulting in the G₂/M transition arrest. Our results provide the first experimental evidence that a novel fatty acid isolated from A. spinosus exhibits significant antiproliferative activity mediated through the induction of apoptosis in HepG2 cells. These encouraging results may facilitate the development of A. spinosus fatty acid for the prevention and intervention of hepatocellular carcinoma.

A new ester of fatty acid from a methanol extract of the whole plant of Amaranthus spinosus and its α-glucosidase inhibitory activity

CONTEXT

Amaranthus spinosus Linn. (Amaranthaceae), commonly known as "spiny pigweed", is used both in the Indian traditional system and in folk medicine to treat diabetes.

OBJECTIVE

The present study evaluates the scientific basis of antidiabetic activity of chloroform fraction of methanol extract of A. spinosus and of an isolated constituent of A. spinosus.

MATERIALS AND METHODS

HPLC analysis was performed to determine the purity and the amount of the constituent present in the plant extract. The yeast α-glucosidase inhibition technique was used to determine the antidiabetic activity of A. spinosus. Acarbose was used as a standard. An appropriate therapeutic approach for preventing diabetes mellitus and obesity is to retard the absorption of glucose by inhibition of α-glucosidase.

RESULTS

One novel fatty acid with strong α-glucosidase inhibitory activity - (14E, 18E, 22E, 26E) - methyl nonacosa-14, 18, 22, 26 tetraenoate [1] (IC50 value 6.52 µM/mL) and β-sitosterol [2] were purified. Compound 1 was found to be more potent than the methanol extract. HPLC quantitative analysis revealed that 0.15% of compound 1 and 0.06% of compound 2 were present in the plant extract.

CONCLUSION

This novel fatty acid can potentially be developed as a novel natural nutraceutical for the management of diabetes.