Study On The Chemical Constituents Of Ethyl Acetate Part Of Yunnan Maca And The Screening Of Effective Parts Of Anti Osteoporosis

BACKGROUNDMaca is the hypocotyls of Lepidium meyemii belonging to the family of Brassicaceae,an annual or biennial herbaceous plant.It is mainly domesticated in the central Andes of South America at elevations of 3500-4500 m above sea level.Its underground storage hypocotyls have been a traditional medicinal agent for long time.In addition,Maca is rich in nutrients and contains many secondary metabolites,such as macaene,macamides,alkaloids,gluconsionlates,isothiocyanate,sterol and polyphenols etc.Pharmacological effects of Maca are commonly used to improve fertility,improve sexual function and treatment of female climacteric syndrome.Maca is divided into black,purple,red,yellow and other varieties according to different colors.With the rapid expansion of Maca in consumer market,the origin of Maca already in short supply.Many countries have introduced the plant,China also introduced Maca.At present,maca are planted mainly in Yunnan,Tibet,Jilin,But the quality of introduced Maca is still need to study.Osteoporosis is a common problem in aging society.The incidence of osteoporosis mainly occurred in postmenopausal women and elderly people.Hormone replacement therapy(HRT)has been proven to be efficacious in preventing bone loss and reducing the incidence of skeletal fractures.However,long-term HRT may cause breast cancer,coronary heart disease,thromboembolic,vaginal bleeding and other adverse symptoms.For these reasons,alternative treatments with less adverse effects are needed.In previous studies,several researchers had found that Maca can improved bone metabolism,but the effective components and mechanism is not clear.The anti-osteoporosis effect of introduced of Maca remains to be further studied.ObjectiveIn this paper,the materials are the yellow Maca produced in Heqing country of Yunnan.This paper studied the chemical constituents of ethyl acetate extract of Maca,investigated the effect of anti-osteoporosis and screened the effective part of antiosteoporosis.Methods1.Study on the chemical constituents of ethyl acetate extract of Maca In this paper,the chemical constituents of ethyl acetate from yellow Maca were studied.Isolation and purification were carried out on column chromatography of silica gel,TLC and preparative HPLC.The structures of these compounds were elucidated by physico-chemical properties and spectral date.2.Screening of anti-osteoporosis parts of Lepidium meyemii In the antiosteoporosis experiment,the there-month-old Kunming female mice with osteoporosis induced by retinoic acid were used as animal model.Retinoic acid was administered for 30 days to establish osteoporosis model.Then continued to give retinoic acid in the morning,at the same time,ethanol extract of Yunnan Yellow Maca and its ethanol extract and aqueous extract,n-butanol extract,ethyl acetate extract,petroleum ether extract are treated continuously for 28 days.After the withdrawal of 24 hours,the mice were killed,visceral organ indexes and weight were calculated;The serum alkaline phosphatase,acid phosphatase and calcium content were determined;The dry weight,length and diameter of the right femur were weighed;The left femur bone mineral density and trabecular number,thickness and spacing was measured;The second lumbar vertebrae were made into bone tissue section to observe the number and density of trabecular bone.Results1.Study on the chemical constituents of ethyl acetate extract of Lepidium meyemii Eight compounds were isolated from Lepidium meyenii,which were identified as N-benzyl-palmitamide(1),?-sitosterol(2),N-benzyl-octadecanamide(3),Pinoresinol(4),Benzeneacetamide(5),?-daucosterol(6),Uracil(7),Pionresinol-4?-O-glucoside(8).One compound(8)are isolated from Lepidium meyenii for the first time.2.Screening of anti-osteoporosis parts of Lepidium meyemii We find that all parts of Maca extract improved the phenomenon of osteoporosis caused by retinoic acid in different degrees.The n-butanol extract and aqueous extract of Maca can significantly improve the visceral indexes of spleen and ovary,but other extract group had no significant effect.The ethanol extract and aqueous extract have significantly improved on the model group.Aqueous extract had the most significant effect on femur physical parameters,followed by n-butanol extract and ethanol extract,while the low polar fraction of petroleum ether had little effect.Polar part in Maca extract had better effect on metal loss in the femur induced by retinoic acid.Aqueous extract can significantly improve BMD,Tb.N,Tb.Th,Tb.Sp.The results showed that the trabecular bone state of pathological tissue was consistent with the bone microstructure,The ethanol extract,n-butanol extract and aqueous extract had better effects on the improvement of bone structure and microstructure.Conclutions1.Eight compounds were isolated from Lepidium meyenii,compound 8 was isolated from Lepidium meyenii for the first time.2.The result show that the Maca grown in Heqing County Yunnan Province possesses anti-osteoporosis activity and the most effective components are mainly concentrated in the aqueous extract.