Introduction
Lotus leaf extract is the dried leaf extract of Nelumbonucifera Gaertn., a plant of the Nymphaeaceae family. It mainly contains alkaloids, flavonoids, volatile oils and other ingredients. Flavonoids are scavengers of most oxygen free radicals and have significant effects in the treatment of coronary heart disease, hypertension and other diseases, and have antibacterial and anti-inflammatory effects; they can be used as raw materials for cardiovascular diseases and can also be widely used in Functional foods, health foods, beverages, food preservatives and cosmetics.
Chemical composition
1.Alkaloids
In the early days, three monomer components, nuciferine, roemerine and O-nornuciferine, were isolated from lotus leaves. Nowadays, many alkaloid compounds have been isolated from lotus leaves. . Lotus leaf alkaloids can be divided into the following three categories according to the different structures of the mother core. Monobenzylisoquinolines, aporphines and dehydroaporphines
2. Flavonoids
There are 16 flavonoids isolated from lotus leaves, most of which have quercetin as the core. The sugar chains include glucose, xylose, galactose, rhamnose, etc., and there are also kaempferol and myricetin derivatives. .
3. Organic acids
Tartaric acid (tartaricacid), citric acid (citricacid), malic acid (malicacid), oxalic acid (oxalicacid), gluconic acid (maltonicacid), succinic acid (aberacid), etc.
4. Volatile oils
cis-3-hexenol and trans-2-pentenol, 1-penten-3-ol, trans-2-hexenal, etc.
Other ingredients also include β-sitosterol, carotene, organic acids, lotus leaf polysaccharides, fatty acids, proteins and trace elements.
Effects
1. Antibacterial effect
Lotus leaf ethanol extract has a certain antibacterial effect on Penicillium, yeast, Aspergillus niger and red yeast, but the antibacterial effect on yeast and red yeast is better than that on Penicillium and Aspergillus niger, and As the concentration of the extract increases, the antibacterial effect increases.
2. Weight loss and lipid-lowering effect
Lotus leaf flavonoids can significantly reduce serum cholesterol (TC), reduce serum triglyceride (TG), reduce body weight and increase serum HDL-C, HL and LPL enzyme activities in hyperlipidemia rats. Lotus leaf extract can reduce the body's digestive capacity, reduce the absorption of lipids and carbohydrates, and strengthen the regulation of lipid metabolism and energy loss, thereby effectively resisting obesity.
3. Antioxidant effect
Modern electron spin resonance spin trapping technology was used to study the scavenging effect of lotus leaf water extract (LLE) on hydroxyl radicals (·OH) and superoxide anion radicals (O2-·). The results show that the clearance rate of 26.94ìg·mL-1 LLE for O2-· produced by the hypoxanthine-xanthine oxidase system reaches 65.6%. When the LLE concentration is greater than 8.98 mg·mL-1, all O2-· produced by the Fenten reaction system can be removed. ·OH, about 40ìg·mL-1 of LLE can remove O2-·. It can be seen that the water extract of lotus leaf is a good antioxidant and can show very strong antioxidant ability at a low concentration. And the antioxidant activity of lotus leaf methanol extract is equivalent to BHA and slightly higher than á-tocopherol.
4. Anticonvulsant effect
Nuciferine does not selectively inhibit neuronal excitation induced by amino acids. Nuciferine has an inhibitory effect on the nerve excitation caused by glutamate, but has a weak inhibitory effect on the nerve excitation caused by aspartate, and has no inhibitory effect on the excitability induced by acetylcholine.
5. Antispasmodic effect
Lotus leaf extract contains nuciferine substances, which have an antispasmodic effect on smooth muscles.
6. Antihypertensive effect
Lotus leaf infusions and decoctions can directly dilate blood vessels and cause moderate antihypertensive effects in animal experiments.
7.Anti-inflammatory effects
Alkaloids have anti-viral, anti-inflammatory and anti-allergic effects; total alkaloids have anti-mitotic effects and inhibit pancreatic lipase; lotus leaf extract has the effect of inhibiting HIV proliferation.
Application:
Lotus leaf extract can significantly inhibit the pathogenic bacteria that cause gingivitis. Currently, lotus leaf extract has been used in toothpaste products, and a qualitative and quantitative detection method for its active ingredients (flavonoids) in toothpaste has been established.
It can also effectively reduce fat and remove oil, and can be used in various weight loss and slimming products.
Extraction and Separation
After 20kg of dried lotus leaf samples were crushed, 12 times the volume of 70% ethanol was used for reflux extraction twice, each time for 2 hours. The extracts were combined and concentrated under reduced pressure to obtain 30L of concentrated solution. The concentrated solution was extracted three times with ethyl acetate and twice with n-butanol. After concentration, 495g of the ethyl acetate portion (Part A) and 700g of the n-butanol portion (Part B) were obtained.
495g of the ethyl acetate part (Part A) was roughly separated by silica gel column chromatography, and petroleum ether-acetone gradient elution (1:0~10:1~3:1~0:1) was used to obtain 4 parts A1~A4, of which the A2 part was silica gel. Column chromatography was performed using petroleum ether-acetone (1:0~30:1) gradient elution to obtain compounds 1 (28 mg), 2 (230 mg), 3 (20 mg), 4 (22 mg), 23 (28 mg), and 24 (48 mg). ), part A3 was separated by silica gel column chromatography using petroleum ether-acetone (10:1~0:1) gradient elution to obtain FrA3-1 and FrA3-2, of which FrA3-1 was separated by silica gel column chromatography using petroleum ether-acetone (5:1). 1) Elute to obtain 21 (56 mg) and 22 (17 mg). FrA3-2 silica gel column chromatography is eluted with petroleum ether-acetone (3:1) to obtain 5 (25 mg). Part A4 is separated by silica gel column chromatography with petroleum ether. -Gradient elution with acetone (3:1~25:1) gave 6 (29 mg), 7 (16 mg), and 25 (20 mg).
700g of the n-butanol part (Part B) was roughly separated by D101 macroporous resin, and eluted with gradients of water, 30%, and 50% ethanol to obtain 3 parts B1 to B3. Part B1 was separated by silica gel column chromatography using chloroform-methanol. -Water (40:8:1) eluted to obtain compounds 14 (10mg), 15 (10mg); chloroform-methanol-water (30:8:1) eluted to obtain compound 10 (150mg), and then, this part The 13th portion (Fr.13) collected was passed through SephadexLH-20 (methanol elution) to obtain compound 8 (12 mg), and the 14th portion (Fr.14) was passed through SephadexLH-20 (methanol elution) to obtain compound 9 ( 14mg); finally, eluted with chloroform-methanol-water (20:8:1), the 15th portion (Fr.15) obtained was passed through SephadexLH-20 (methanol elution) to obtain compounds 11 (15mg), 12 (8mg) ), the 16th fraction (Fr.16) was passed through SephadexLH-20 (elution with methanol) to obtain compound 13 (6 mg). Part B2 was separated by silica gel column chromatography and eluted with chloroform-methanol-water (40:8:1～0:0:1) to obtain compound 27 (15 mg). Part B3 was eluted with chloroform-methanol-water (240:20:1) to obtain compounds 16 (28mg) and 20 (85mg). The 31st fraction (Fr.31) collected by elution was then washed with SephadexLH-20 (methanol). (removal) gave compound 17 (14 mg). The 34th portion was eluted with SephadexLH-20 (methanol elution) to obtain compound 18 (11 mg), and the 35th portion was eluted with chloroform-methanol-water (120:20:1) to obtain compounds 19 (120 mg) and 26 (13 mg). 27 compounds were isolated.
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