Spasmolytic effect of Alternanthera repens on isolated rat ileum

The Genus Alternanthera: Phytochemical and Ethnopharmacological Perspectives

Ethnopharmacological relevance: The genus Alternanthera (Amaranthaceae) comprises 139 species including 14 species used traditionally for the treatment of various ailments such as hypertension, pain, inflammation, diabetes, cancer, microbial and mental disorders.

Aim of the review: To search research gaps through critical assessment of pharmacological activities not performed to validate traditional claims of various species of Alternanthera. This review will aid natural product researchers in identifying Alternanthera species with therapeutic potential for future investigation.

Materials and methods: Scattered raw data on ethnopharmacological, morphological, phytochemical, pharmacological, toxicological, and clinical studies of various species of the genus Alternanthera have been compiled utilizing search engines like SciFinder, Google Scholar, PubMed, Science Direct, and Open J-Gate for 100 years up to April 2021.

Results: Few species of Alternanthera genus have been exhaustively investigated phytochemically, and about 129 chemical constituents related to different classes such as flavonoids, steroids, saponins, alkaloids, triterpenoids, glycosides, and phenolic compounds have been isolated from 9 species. Anticancer, antioxidant, antibacterial, CNS depressive, antidiabetic, analgesic, anti-inflammatory, and immunomodulator effects have been explored in the twelve species of the genus. A toxicity study has been conducted on 3 species and a clinical study on 2 species.

Conclusions: The available literature on pharmacological studies of Alternanthera species reveals that few species have been selected based on ethnobotanical surveys for scientific validation of their traditional claims. But most of these studies have been conducted on uncharacterized and non-standardized crude extracts. A roadmap of research needs to be developed for the isolation of new bioactive compounds from Alternanthera species, which can emerge out as clinically potential medicines.

Toxicity against Drosophila melanogaster and antiedematogenic and antimicrobial activities of Alternanthera brasiliana (L.) Kuntze (Amaranthaceae)

Bioactive phytocompounds are studied by several bioactivities demonstrated, as their cytotoxic effects. The aim of this work was to evaluate the phytochemical profile, the toxic effect using the Drosophila melanogaster animal model and the anti-inflammatory and antimicrobial effect of the Alternanthera brasiliana (EEAB) ethanol extract. The phytochemical profile was performed using HPLC. The cytotoxic effect was evaluated in vivo using D. melanogaster. The anti-inflammatory effect was determined by neurogenic and antiedematogenic assays, and the antimicrobial activity was assayed using a microdilution method to determine the minimum inhibitory concentration (MIC) of the EEAB alone and in association with antibiotics. The main compound identified on the EEAB was luteolin (1.93%). Its cytotoxic effect was demonstrated after 24 h in the concentrations of 10, 20 and 40 mg/mL. The extract demonstrated an antiedematogenic effect, with a reduction of the edema between 35.57 and 64.17%. The MIC of the extract was ≥1.024 μg/mL, thus being considered clinically irrelevant. However, when the EEAB was associated with gentamicin, a synergism against all bacterial strains assayed was observed: Staphylococcus aureus (SA10), Escherichia coli (EC06) and Pseudomonas aeruginosa (PA24). Due to these results, the EEAB demonstrated a low toxicity in vivo and anti-inflammatory and synergistic activities. These are promising results, mainly against microbial pathogens, and the compounds identified can be a source of carbon backbones for the discovery and creation of new drugs.