| Lotus (Nelumbo nucifera Gaertn.), a traditional Chinese herb, is extensively cultivated in China. The cultivation area of lotus is 6 to 7.3 million ha. mainly in Hubei, Hunan, Jiangxi, Fujian, Jiangsu, Zhejiang, Shandong. Hebei and other provinces. Hubei Province, about 1 million ha, is ranking first in the chinese cultivated area. However, the utilization of lotus is very low. We can see a lot of lotus leaf becoming waste every year. We believe that lacking of relative product of lotus leaf, and low market demand seriously hampered the rational using of the resources. Therefore, present study focused on evaluation of the potent antioxidant, hepatoprotective, meat preservation and anti-UVB activities. Research on the lotus leaf may help to broaden its application in medicine, resulting in greater use of this abundant resource, providing income for lotus producers and the regional economy. The main results are as following:(1) Examining the composition of extracts and essential oil components from lotus leaf from the principal habitats in China. All the extracts had strong antioxidant activity in comparison to the standard compounds BHT and vitamin C. Wild lotus samples from Baiyangdian Lake and Weishan Lake exhibited a stronger free radical scavenging effect and greater reducing power than the cultural samples, but no such differences were observed in the inhibition of lipid oxidation. Chemical variation in the essential oils from the various samples was analyzed by GC-MS. The main constituents were 1-(+)-ascorbic acid 2,6-dihexadecanoate (0-33.5%), trans-phytol (5.1-24.1%), hexahydrofarnesyl acetone (5.6-15.3%), pentadecyl acrylate (2.2-12.4%), geranyl acetone (1.9-8.0%), andβ-ionone (0-8.0%). The rhizome lotus and seed lotus samples were clustered into separate groups by hierarchical cluster analysis according to the composition of the corresponding essential oils. No significant relationship was found between essential oil composition and geographical distribution of the eleven populations. However, our results indicated that region of origin and growing conditions could significantly affect both the bioactivities of the lotus leaf and the content of bioactive compounds in the leaves. Our study demonstrated the existence of chemical polymorphism in the Nelumbo nucifera leaf in China.(2) An extract of the leaf was studied for its antioxidant activity in vitro and in vivo. The total phenolic and total flavonoid content of the LLE are determined to be 37.4% and 20.3%, respectively. In the DPPH and ABTS scavenging assay, the IC50 values of LLE were 4.172μg/mL and 2.195μg/mL, respectively. LLE showed similar radical scavenging activity to that of the synthetic antioxidant BHT and Vc. And, LLE has strong reducing power. The LLE also showed strong activity against lipid peroxidation. The results of antioxidant activity in vivo showed that LLE treatment reduced elevated MDA and increased SOD, CAT, and GSH levels back to their control levels indicated that LLE may prevent the peroxidation of lipids by CCl4. The main flavonoids and phenolic compounds of LLE were analyzed by HPLC-DAD-ESI/MS methods. Six of the compounds detected were tentatively characterized, one as catechin glycoside and five as flavonoid glycoside derivatives:miricitrin glucoside, hyperin, isoquercitrin, quercetin rhamnoside and astragalin.(3) An extract of the lotus leaf was studied for its hepatoprotective activity against CCl4-induced liver toxicity in rats. Activity was determined by monitoring the level of alanine aminotransferase, aspartate transaminase, alkaline phosphatase, y-glutamyltransferase, and total bilirubin. The results showed hepatoprotective activity of lotus leaf extract at doses of 300 and 500 mg/kg that was comparable with a standard treatment comprising 100 mg/kg of silymarin. These data were supplemented with histopathological studies of rat liver sections.(4) Extracts from lotus rhizome knot (LRK) and lotus leaf (LLE) are proposed as preservatives for increasing the antioxidant activity of Porcine and bovine. Raw and cooked samples were stored and the antioxidant activity was Antioxidant activity was significantly increased in all meat samples with the addition of both LRK and LL, but LRK was more effective against lipid oxidation. Our results suggest the potential for using LRK and LL extracts in the meat industry to prolong food storage times by reducing spoilage. Emerged in the activity of two extracts may be related to differences in the type of major phenolic compounds, lotus leaf extract containing mainly flavonoids. lotus rhizome knot extract containing mainly tannins.(5) An extract of the lotus leaf was studied for its photoprotective activity against UVB-induced phototoxicity by measuring malondialdehyde, lipid hydroperoxide, conjugated diene, glutathione and 4-hydroxynonenal. The results showed that LLE had excellent protective activates of lipid peroxidation (LPO), 4-hydroxynonenal and antioxidant reduction against UVB-induced phototoxicity.In conclusion, this work was systematically focused on the lotus leaf’s antioxidant, hepatoprotective, meat preservation and anti-UVB activities. These may help to broaden its application in medicine and food industry, resulting in greater use of this abundant resource, providing income for lotus producers and the regional economy. |
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