Seasonal Effects on Phenolic Contents and In Vitro Health-Promoting Bioactivities of Sacred Lotus (Nelumbo nucifera)

Abstract

Sacred lotus (Nelumbo nucifera) is a commercial product in Asian countries. Almost all parts of the lotus plant are consumed as food or used as traditional medicine due to their high contents of secondary metabolites such as phenolics and alkaloids. However, agricultural management of the sacred lotus occurs during the rainy season, and the plant enters a resting stage during the dry season. Thus, seasonal variation (beginning, middle and end of the rainy season) was investigated for total phenolic contents (TPCs), antioxidant capacities and inhibitions of the key enzymes relevant to chronic diseases including Alzheimer’s disease (β-secretase, acetylcholinesterase and butyrylcholinesterase), hypertension (angiotensin-converting enzyme), obesity (lipase) and diabetes (α-glucosidase) of different sacred lotus parts (seed embryo, petal, stamen, old leaf, leaf stalk and flower stalk). Results indicated that an aqueous extract of stamen in all harvesting seasons exhibited potentially high TPCs, which led to high antioxidant activities and most enzyme inhibitions (up to 53.7-fold higher) than the others collected in the same harvesting period. The phenolic content and biochemical activities in stamen harvested at the beginning of the rainy season were up to 4-fold higher than during other harvesting periods. This information benefits the agricultural management of sacred lotus and supports consumption of different sacred lotus parts for health promotion. Results can be used as an initial database for future product development from different sacred lotus parts.

Phenolic profiles and in vitro biochemical properties of Thai herb ingredients for chronic diseases prevention

“…High TPCs in CSA gave high antioxidant potential in both HAT and SET mechanisms. A strong correlation between TPCs and antioxidant activities was also observed in rice, sacred lotus, and other plant extracts 12 , 16 , 23 , while water extract of CSA stem bark exhibited TPC of 682.67 mg GAE/g extract and DPPH radical scavenging activities with IC 50 of 9.47 µg/mL as the highest among 16 galactogogue medicinal plants in Northeastern Thailand 24 . This TPC value corresponded to our 70% ( v/v ) aqueous ethanolic extract of CSA with TPC of 728.50 mg GAE/g extract.…”

“…Myristica fragrans seed extract showed a downregulated effect on the expression of lipid genes, resulting in anti-obesity activity and preventing non-alcoholic fatty liver disease 9 , while a root extract of A. dahurica showed vasorelaxant activity and attenuated hypertension in animal model 10 . Nelumbo nucifera pollen extract inhibited aldose reductase, the enzyme associated with diabetic complication 11 , while many parts of this plant exhibited inhibitory effect against many key enzymes relevant to Alzheimer’s disease, hypertension, obesity, and diabetes 12 , 13 .…”

Optimized Conditions for the Extraction of Phenolic Compounds from Aeginetia indica L. and Its Potential Biological Applications

“…These phenolics might contribute to the antioxidant and enzyme-inhibitory activities detected in A. indica. A strong correlation between TPC and antioxidant activities was previously reported in many plant extracts [27,28]. However, only the total antioxidant capacity (TAC) measured by the phosphomolybdenum assay (68.3 mg ascorbic acid equivalent/g extract) of A. indica was previously reported [3].…”