Chinese herbal extract, preparing method and application thereof Field of the invention The present invention relates to cosmetics field, particularly to an extract of Chinese 5 herbal medicines, its preparation and use, as well as a Chinese herbal medicine composition containing the extract of Chinese herbal medicines having anti-aging effect, its preparation and its use in cosmetics. Background of the invention 10 The main functional supportive additives in current most anti-aging cosmetics in domestic and foreign market are biochemical agents and synthesized compounds. Anti-photo aging products have been released one by one; and more related researches are being conducted. However, the current commercially available cosmetics using natural products or plant extracts as the additive are mostly based on 15 the pharmacological research of a single Chinese herbal medicine in absence of the guidance of Chinese medicine theory and the research on the combination of the Chinese herbal medicine. Additionally, the current commercially available Chinese herbal medicines anti-aging cosmetics are mostly the simple combination of the extracts of the single Chinese herbal medicines without the guidance of Chinese 20 medicine theory; or the extraction method is complex with the increased costs. Description of the invention The technical problem to be solved by the present invention is to provide an extract of Chinese herbal medicines, which has the anti-aging efficacy. 25 In order to achieve the above objective, the extract of Chinese herbal medicines according to the present invention is an water and/or solvent extract of 30-70 parts by weight of Rhizoma Polygonati, 30-70 parts by weight of Rhizoma Polygonati Odorati, and 0.01-5 parts by weight of gold foil, wherein said solvent is selected from 30 methanol, ethanol, isopropanol, n-butanol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, acetone, ethyl acetate or combinations thereof. The "Rhizoma Polygonati" used herein is the dried roots and stems of Liliaceae plant Polygonatum kingianum Coll. et Hemsl., Polygonatum sibiricum Red, or 1 Polygonatum cyrtonema Hua., which is also known as tiger ginger or jitou ginseng. Rhizoma Polygonati can be classified into three types of ginger-shaped Rhizoma Polygonati, jitou Rhizoma Polygonati, and big Rhizoma Polygonati based on the difference of properties of the original plants and the medicinal materials. The 5 original plant of ginger-shaped Rhizoma Polygonati is Polygonatum cyrtonema Hua., the original plant of jitou Rhizoma Polygonati is Polygonatum sibiricum Red, and the original plant of big Rhizoma Polygonat (also known as papilionaceous Rhizoma Polygonati) is Polygonatum kingianum Coll. et HemsL.. Among these, the ginger-shaped Rhizoma Polygonati has the best quality. Polygonatum sibiricum Red 10 is distributed in various provinces of North China and Anhui, Zhejiang, Gansu, and the far east of the former Soviet union. Polygonatum cyrtonema Hua. is mainly distributed in various provinces of South China, Shanxi, Gansu and south of Northeast China. Polygonatum kingianum Coll. et Hemsl. is distributed in Guizhou, Yunnan, Guangxi, Sichuan of China. 15 Rhizoma Polygonati is sweet in flavor, has moderate properties. It can nourish kidneys and lungs, invigorate spleen and boost qi, and has anti-hypoxia, anti-fatigue, and anti-aging effects, and can also enhance immune function, and improve metabolism. It contains various active ingredients such as aspartic acid, digitalis 20 glycosides, anthraquinones, phlegm, carbohydrate, nicotinic acid, and the like. "Valuable prescriptions for emergency" recited that the administration of Rhizoma Polygonati paste can "remove old skin, brighten face, alter flower color and change eyebrow and mustache". 25 The "Rhizoma Polygonati Odorati" used herein is the dried roots and stems of Liliaceae plant Polygonatum odoratum (Mill.) Druce. Polygonatum odoratum(Mill.) Druce is native to Southwest China, but the wild-types are widely distributed. It is resistant to cold and shade, and is fond of humid environment. It is suitable for growing in the chessom rich in humus. 30 Rhizoma Polygonati Odorati is sweet in flavor, has moderate properties. It can nourish kidneys and lungs, invigorate spleen and boost qi. It belongs to Liliaceae Polygonatum. "Shen Nong's herbal classic" listed it as a top grade medicine, and recited that "it can eliminate dark face, beautify and make lenitive by long administration". It contains various bioactive nutrient substances such as polysaccharides, alkaloids, cardiac glycosides, vitamin A and the like, and is a classical top grade cosmetics for taking internally and external use. 5 In application of Chinese medicine, gold foil can be added into medicines and decocted into an elixation; or acts as a coating of a pellet similar to the external sugar-coating of the modern medicines. The most famous Angong Niuhuang pill is a medicine coated with a gold foil. The gold can be used to enhance the effect of tranquilization of medicines. "Tai Ping Sheng Hui Fang", "Valuable prescriptions" 10 and "Shengji Zonglu" all recited the treatment by eating the gold foil. Additionally, in the use of acupuncture, the acupuncture needle made of pure gold or alloy has the better effect of guiding flow of qi and blood. Modem pharmacological researches show that the polygonatum polysaccharides is one of the main active principles of Rhizoma Polygonati and has the effects of anti-tumor, anti-aging, immune regulation 15 and anti-oxidative damage, and the like. The pharmacological action of Rhizoma Polygonati Odorati mainly lies in the effects of anti-aging, improving the ability of the immune system of the body, lowering blood glucose and blood lipid, anti-tumor, and the like. According to the experiment carried out by Gifu University of Japan with the water exact of Rhizoma Polygonati Odorati, it can significantly inhibit aging 20 of the skin and has an effect of beautifying the skin. Polysaccharide of Rhizoma Polygonati Odorati has the enhanced free radical scavenging capacity, can inhibit lipid peroxidation, reduce malondialdehyde and reduce tissue damage to delay aging. The present invention also provides a preferred method for preparing the extract of 25 Chinese herbal medicines, comprising: Extracting the material consisted of 30-70 parts by weight of Rhizoma Polygonati, 30-70 parts by weight of Rhizoma Polygonati Odorati with water and/or solvent, wherein said solvent is selected from methanol, ethanol, isopropanol, n-butanol, 30 ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, acetone, ethyl acetate or combinations thereof. Preferably, the method further comprises: 3 Adding alcohol to the extract to obtain a precipitate; adding water to dissolve the precipitate; filtering; formulating the filtrate into a solution. Preferably, the extracting is carried out by a method selected from decoction, 5 refluxing and extracting, soaking, diacolation or a combination thereof. Preferably, the alcohol for obtaining the precipitate is selected from methanol, ethanol, isopropanol, n-butanol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, or combinations thereof, preferably, it is ethanol. 10 Preferably, the precipitate is purified by membrane-dialysis separation after it is dissolved by adding water. The dialyzate is formulated into a solution. Preferably, ultrafiltration is used during the membrane-dialysis separation. 15 Preferably, the membrane used in the ultrafiltration has a pore size of 100,000 Dalton. The extract of Chinese herbal medicines according to the invention has anti-aging effect and can be used in cosmetics. 20 The present invention also provides an anti-aging Chinese herbal medicine composition containing the above extract of Chinese herbal medicines. The extract of Chinese herbal medicines according to the invention has effects of 25 emollient, repairment, protection and regeneration and has no stimulation to the skin. It can be directly applied in anti- aging of the skin, and can also be used as an additive of cosmetics, and has low cost. Embodiments 30 The present invention will be further described in detail with reference to the following examples. Example 1 Pure Chinese medicinal materials of Rhizoma Polygonati 30g and Rhizoma 4 Polygonati Odorati 70g for a total weight of 100g were mixed thoroughly, to which 10-fold amount (fold amount refers to the ratio between the volume of the solvent (ml) and the total weight of the medicinal materials (g), hereinafter the same) of water was added. The mixture was kept for decoction for about lh and then filtered to remain 5 the filtrate. The residue was added 10-fold amount of water for decoction for about 1h and then filtered to remain the filtrate. The filtrate was combined with the former filtrate, concentrated, added a suitable amount of ethanol and stood for 24h; filtered, the precipitate was added water to be dissolved and purified by membrane separation device ( Device type: RNF0460 roll membrane, membrane pore size: 100,000 Dalton, 10 Supplier: Xiamen Shida Membrane Technology Co., Ltd.), and the membrane dialysate was made to a solution with a concentration of crude drug of 500 mg/ml, thus obtaining extract solution A. Example 2 15 Pure Chinese medicinal materials of Rhizoma Polygonati 70g and Rhizoma Polygonati Odorati 30g for a total weight of 100g were mixed thoroughly, to which 10-fold amount of 75% ethanol was added. The mixture was kept for refluxing and extracting for about lh and then filtered to remain the filtrate. The residue was added 10-fold amount of 75% ethanol for refluxing and extracting for about 1h and 20 then filtered to remain the filtrate. The filtrate was combined with the former filtrate, and the ethanol was recovered to dryness. The extract was dissolved by water, filtered to make a solution with a concentration of crude drug of 500 mg/ml, thus obtaining extract solution B. 25 Example 3 Pure Chinese medicinal materials of Rhizona Polygonati 40g and Rhizoma Polygonati Odorati 60g for a total weight of 100g were mixed thoroughly, to which 10-fold amount of 30% propylene glycol was added. The mixture was kept for soaking for 24h and then filtered to remain the filtrate. The residue was added 30 10-fold amount of 30% propylene glycol for soaking for 24h and then filtered for the recovery of a part of water to make a Chinese herbal medicine solution C with a concentration of crude drug of 500 mg/ml. Example 4 Pure Chinese medicinal materials of Rhizoma Polygonati 30g and Rhizoma Polygonati Odorati 70g for a total weight of 100g were mixed thoroughly, to which 10-fold amount of water was added. The mixture was kept for decoction for about 1 h and then filtered to remain the filtrate. The residue was added 1 0-fold amount of 5 water for decoction for about 1h and then filtered to remain the filtrate. The filtrate is combined with the former filtrate, concentrated, added a suitable amount of ethanol and stood for 24h; after filtered, the precipitate was added water to be dissolved and to be made into a solution with a concentration of crude drug of 500 mg/ml, thus obtaining extract solution D. 10 Experiment 1 DPPH experiment Free radical is a class of chemicals with activity and extremely high oxidbillity. 15 Unstable free radicals produced during metabolism of the body are deposited in the cells, resulting in that the unsaturated fatty acids are oxidated into peroxide to form lipofuscin (LF), and that the cells and the important components thereof such as DNAs, proteins and enzymes are altered or destroyed, leading to the aged body. Reduction of the free radical damage to the body can play a role in anti-aging. 20 DPPH is an important method for evaluating ability of scavenging free radical and the antioxidant ability of the sample. The extracts of the examples were diluted with distilled water to two concentrations, 0.2%, 1%, 5% and 25% (v/v), respectively. Two milliliters of each of the diluted 25 extracts of the Examples, 0.5 ml of DPPH solution in ethanol at a concentration of 500 tmol/L, and 1.5ml of water were then sequentially added into a same test tube and shaken thoroughly. After being stood for 30 min, its optical density (OD) was measured at 517 nm by using a corresponding mixture liquid as the blank control. The scavenging rates for DPPH of the extracts of the examples were calculated according 30 to the following formula: The scavenging rate (%) - * 100 % C wherein: T -- the optical density of DPPH + the extracts of the Examples, 6 TO -- the optical density of the extracts of the examples + solvents, C -- the optical density of DPPH + solvents. The results of evaluation on the anti-oxidation ability of the Chinese herbal medicine 5 extracts and compositions obtained from each Example were shown in Table 1. Table 1 Concentration 5% 1% 0.2% Free radical Scavenging Rate (%) Extract solution A of Example 1 43.8% 27.1% 5.1% Extract solution B of Example 2 42% 23.6% 5.2% Extract solution C of Example 3 41.8% 22.2% 4.9% Extract solution D of Example 4 43.5% 24.2% 6.3% The results of the experiments showed that, the extracts of Examples 1-4 have 10 superior antioxidant ability for free radical scavenging at the concentrations of 0.2%, 1% and 5%, wherein all the free radical scavenging rates at the concentration of 5% are greater than 40% and all the free radical scavenging rates at the concentration of 1% are greater than 20%, and the effect from the extract A of Example 1 is the best. 15 Experiment 2- proliferation experiment of fibroblast The fibroblast in the skin is the main cells for collagen synthesis. The large amount of proliferation of fibroblast, or the enhanced ability of fibroblast for synthesizing and secreting collagen can all increase the total amount of collagen, thus postponing the skin aging. Hence, studying the effect of promoting proliferation of fibroblast is one 20 of the important methods for evaluating the anti-aging activity of the sample. The present experiment uses the method of culturing human fibroblast in vitro and preliminarily evaluates the anti-aging effect of the Chinese herbal medicine composition according to the present invention based on the above skin aging mechanism. 25 The prepared cell suspension (formulated into a concentration of 5*10 3 /ml) was seeded into a 96-well plate. Except for the blank control, 20 111 extract of Chinese herbal medicines of Examples with corresponding concentrations was added to each well after the cell attachment. 4 concentration groups were set with 6 wells per 7 group. The plate was placed into an incubation chamber (37 'C and 5% CO 2 ) to incubate for 48h, then 20 11 1 MTT solution was added. The plate was continued to incubate in the incubation chamber (37 'C and 5% CO 2 ) for 4h. The enzyme panel was taken out, the culture solution in each well was absorbed carefully, the DMSO 5 was added and mixed evenly. The optical density (570 nm) was measured by enzyme-linked immunometric meter and the relative proliferation rate was obtained by comparison with the control. The results of proliferation activity of the anti-aging Chinese herbal medicine 10 composition according to the present invention to the fibroblast were shown in Table 2. Table 2 Concentrations 1% 0.1% 0.01% 0.001% The proliferation rate for promoting dermal fibroblast (%) Extract solution A of Example 1 31.0% 28.7% 28.6% 25.0% Extract solution B of Example 2 27.7% 21% 17.8% 12.5% Extract solution C of Example 3 25.6% 21% 15.6% 10.1% Extract solution D of Example 4 29.3% 25.4% 20.0% 13.2% 15 The results of the experiments indicated that extract A of Example 1, extract B of Example 2, extract C of Example 3 and extract D of Example 4 all can promote the proliferation of the fibroblast and the effect from the extract A of Example 1 is the best, wherein the proliferation rate of fibroblast is promoted to be 25% at a concentration of 0.001%. 20 The above experiments indicated that the Chinese herbal medicine composition according to the invention have antioxidant ability for free radical scavenging in vitro and can promote the proliferation of the fibroblast of the skin and is helpful for anti-aging. 25 8