The rhizome of giant taro (Alocasia macrorrhiza (L.) Schott), which is a highly adaptable wild plant, is a traditional Chinese herbal medicine. In the current study, the antiproliferative constituents of giant taro were investigated and six new (1-6) and four known piperidine alkaloids (7-10) were isolated from its rhizomes. Their chemical structures and absolute configurations were elucidated using various spectroscopic methods and the Mosher ester method. The isolated alkaloids were screened for the antiproliferative activity through MTT assay. The results indicated that piperidine alkaloids exerted potential antiproliferative activity against HepG2, AGS and MCF-7 tumor cells. Further researches showed that compounds 3-5 dose-dependently decreased the colony formation rate and induced the apoptosis of AGS cells, while compound 4 induced AGS cell death via the proapoptotic pathway. This study demonstrates that the piperidine alkaloids isolated from giant taro exhibit significant antitumor activity, which provides phytochemical evidence for further development and utilization.
Alkaloids/pharmacology* ; Alocasia/chemistry* ; Humans ; Piperidines/pharmacology* ; Plants ; Rhizome/chemistry*

OBJECTIVETo elucidate potential antioxidant, antidiarrheal, cytotoxic, and antibacterial activities of the ethanol extract of Alocasia indica Schott tuber in different experimental models established in vitro and in vivo.

METHODSIn vitro antioxidant activity was evaluated by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging assay. Phenolic content was estimated by using Folin-Ciocalteu's reagent while reducing ability was measured by ferric reducing power assay. In vivo antidiarrheal studies were carried out in mice, and the activity was evaluated in castor oil and magnesium sulfate-induced diarrhea. Disk diffusion assay was utilized to determine antibacterial activity against a number of pathogenic bacterial strains. Acute toxicity test was carried out to measure the safe doses for the extract.

RESULTSIn DPPH radical-scavenging assay, the extract exhibited strong radical-scavenging activity with the 50% inhibitory concentration value of 42.66 μg/mL. Total phenolic content was found to be 542.26 mg gallic acid equivalent per 100 g of dried tuber extract, whereas flavonoid content was found to be 4.30 mg quercetin equivalent/g of dried tuber extract. In reducing power assay, the extract showed strong reducing power in a concentration-dependent manner. The extract significantly (P < 0.01) enhanced the latent period and decreased defecation in both castor oil- and magnesium sulfate-induced diarrhea. The extract also lessened gastrointestinal motility in mice. Potential antibacterial activity was exhibited by the extract against all the tested bacterial strains in disk diffusion assay. The 50% lethal concentration against brine shrimp nauplii was 81.09 μg/mL.

CONCLUSIONThe results demonstrated that the ethanol extract of A. indica has potential antioxidant, antidiarrheal, cytotoxic, and antibacterial activity.

Alocasia ; chemistry ; Animals ; Anti-Bacterial Agents ; pharmacology ; Antidiarrheals ; pharmacology ; Antioxidants ; pharmacology ; Artemia ; drug effects ; Female ; Gastrointestinal Motility ; drug effects ; Male ; Mice ; Plant Extracts ; pharmacology ; toxicity