Study On The Improvement Effect Of Camellia Oleifera Leaves Extract On Acne

Acne is a global disease and the most common chronic inflammatory skin disease involving the sebaceous glands.The main cause of acne is the excessive secretion of lipids by the sebaceous glands induced by androgen.5α-Reductase（5α-R）is an important androgen metabolizing enzyme in the skin,which can irreversibly convert testosterone（T）into dihydrotestosterone（DHT）.Reducing DHT levels by inhibiting5α-R activity has become an important way to treat androgen-dependent diseases such as acne.Camellia Oleifera leaves are extremely rich in active substances such as polyphenols and flavonoids.In this paper,Camellia Oleifera Leaves Extract（COLE）with high 5α-R inhibitory activity was prepared by taking Camellia Oleifera leaves as raw materials.In order to explore the effect of COLE on the sebaceous gland spots on the back of golden hamsters and the possible mechanism of action,two modes of administration including external application and gavage were explored.The research results of this paper were as follows:（1）Camellia oleifera leaves extracts with different polar solvents were prepared.Among them,the yield of 50%ethanol extract of Camellia oleifera leaves and the 5α-R inhibition rate were the highest;through Pearson correlation analysis,it was found that the 5α-R inhibition rate of Camellia oleifera leaves extract was highly correlated with the content of total phenols and total flavonoids（r>0.6,r>0.8）;Camellia oleifera leaves extract had outstanding antioxidant capacity,of which 50%ethanol extract had the best effect in removing DPPH·and ABTS^·+;after considering the 5α-R inhibitory activity,yield,total phenol and total flavonoids and other perspectives,finally selected50%ethanol as the best extraction solvent to prepare the corresponding extract COLE;The inhibitory effect of COLE on 5α-R showed a dose-effect,with IC₅₀ of 259.56μg/m L,and 39.35 mg/d COLE was effective as 0.5 mg/d dutasteride clinically.It is confirmed that COLE had a strong 5α-R inhibitory effect and was a potential 5α-R inhibitor.（2）UPLC-Triple TOF-MS/MS was used to analyze and identify the phenolic substances in COLE.As a result,a total of 22 phenolic compounds were inferred,including 8 phenolic acid compounds and their derivatives,10 flavonoids compounds and their derivatives and 4 other compounds.Among them,3-O-galloyl-4,6,-[（S）-hexahydroxybiphthaloyl]-α/β-D-glucopyranose（Gemin D）,quercetin,rutin,catechin,3,4,6-tri-O-galloyl-α/β-D-glucopyranose may be the material basis of COLE to exert5α-R inhibitory activity,and it may also be the result of the joint action of a variety of phenolic compounds.（3）COLE gel and blank gel were prepared,and then the sensory properties,physical and chemical properties were evaluated,and irritation of two gels to make them meet the requirements of quality standards.Using golden hamster sebaceous gland spots as the research carrier by two administration methods,"gavage"and"external application".The results showed that gavage of COLE and external application of COLE gel can make the sebaceous gland spots appear smaller in size and lighter in color;HE staining results indicated that COLE and COLE gel reduce the number of sebaceous glands in golden hamsters and made their arrangement loose,the surrounding gland cells in the glands were reduced,too;the oil red O staining results manifested that COLE can reduce the accumulation of orange-red lipid droplets around the sebaceous glands,and reduce the lipid secretion level of sebaceous gland plaque tissue.（4）Oxidative stress indicators made it clear that the administration of COLE can significantly reduce the severity of free radical attacks in the body;COLE gel has outstanding antioxidative stress ability and can protect the skin;lipid metabolites indicators showed that intragastric COLE can not only reduce the content of serum lipids,but also reduce the sebum content of sebaceous glands;the intervention of COLE gel can also reduce the secretion of lipids in sebaceous glands;the androgen index results proved that gavaging COLE and external application COLE gel had an anti-androgen effect,which can act on the sebaceous glands of golden hamsters,reducing the DHT content by inhibiting the 5α-R activity in the sebaceous gland tissue;gavaging COLE can also reduce the serum DHT level;SRD5A1/AR/SREBP-1c signaling pathway related protein expression results demonstrated that the intervention of COLE and COLE gel can significantly reduce SRD5A1（p<0.01,p<0.01）,AR（p<0.01,p<0.01）.The expression of SREBP-1c（p<0.01,p<0.01）.By activating the SRD5A1/AR/SREBP-1c pathway,COLE reduced the expression level of 5α-R in the sebaceous glands and affects its activity,greatly reducing the amount of DHT produced.At the same time,by inhibiting the expression of AR,it reduced the binding chance of DHT and AR,and then affect the expression of SREBP-1c,so that the content of DHT in golden hamster serum and sebaceous plaque tissue decreased,and the content of lipid metabolites decreased too.In summary,the results of in vitro 5α-R inhibition test and the using of golden hamster sebaceous gland spots to simulate acne treatment together indicated that Camellia oleifera leaves extract has the potential to treat acne.The specific mechanism involves:inhibiting SRD5A1/AR/SREBP1c signaling pathway and reducing 5α-R activity to reduce the content of DHT,then decreasing the lipids secretion of sebaceous glands to exert the effect of acne improving.This research provided new research ideas and theoretical basis for the development and utilization of Camellia oleifera leaves and related products as new natural anti-acne agents and cosmetic additives.