Pharmacodynamics of frigid zone plant Taxus cuspidata S.et Z.against skin melanin deposition,oxidation,inflammation and allergy

Background:Taxus cuspidata S.et Z.is a precious species of frigid zone plant belonging to the Taxaceae family,which possesses anticancer,anti-inflammatory,hypoglycemic,and antibacterial pharmacological properties.While taxane extracted from Taxus chinensis has been reported to elicit antioxidant activities,whether Taxus cuspidata S.et Z.has skin-protective actions against injuries remained unknown.This study aims to explore the pharmacological effects of three Taxus extracts on skin melanin deposition,oxidation,inflammation,and allergy so as to provide new ideas for the prevention and treatment of various diseases related to skin damage.Methods:Skin melanin deposition was evaluated by measuring melanin content in the skin of guinea pigs by alkali lysis method.Antioxidant capacity was evaluated by measuring superoxide dismutase(SOD)concentration and glutathione(GSH)content in skin tissue homogenates of Kunming mice by SOD assay kit and micro reduced GSH assay kit.The quantitative real-time polymerase chain reaction(qRT-PCR)and western blotting were used to examine the levels of both SOD and recombinant glutathione peroxidase 4(GPX4).Skin inflammation was evaluated by xylene-induced ear swelling test and egg-white-induced paw swelling test in mice.In a mouse model of skin allergy induced by 4-aminopyridine(4-AP),allergy was determined by licking body counts and histamine concentrations in tissue homogenates using enzyme-linked immunosorbent assay(ELISA)kits.Two proinflammatory factors tumor necrosis factor(TNF)-αand interleukin(IL)-1βwere measured by qRT-PCR.Hematoxylin and eosin(HE)staining was conducted to assess the degree of skin lesion.Results:All three Taxus extracts including Taxus chinensis essential oil,Taxus chinensis extract and Taxus chinensis extract compound reduced the melanin deposits in the back skin relative to the non-treated control animals,of which Taxus chinensis essential oil produced the greatest effect.In contrast,the three Taxus extracts elevated SOD and GSH levels in the skin tissues,and the highest increase was seen with Taxus chinensis essential oil.Three Taxus extracts,especially Taxus chinensis essential oil,effectively reduce the rate of ear and paw swelling.All three Taxus extracts reduced the number of body licks,the levels of TNF-αand IL-1β,and the histamine content in tissue homogenates of mice and alleviated skin damage.Consistently,Taxus chinensis essential oil yielded the greatest magnitude of decreases.Conclusion:While all three Taxus extracts possessed the anti-skin melanin deposition,oxidation,and allergy properties,Taxus chinensis essential oil produced the superior effects.

HPLC法测定离体大鼠皮肤中鬼臼毒素滞留量

目的测定鬼臼毒素醇质体皮肤局部用药后，离体大鼠皮肤中鬼臼毒素的滞留量。方法建立HPLC法测定离体大鼠皮肤中鬼臼毒素的含量。色谱柱为Diamonsil C18，流动相为甲醇-1％醋酸（65：35，V／V），流速为1．0mL·min-1，内标为依托泊苷，检测波长为292nm，柱温为25℃。进行体外实验，采用该方法测定鬼臼毒素醇质体皮肤局部用药2，4，6，8，12h后，大鼠皮肤中鬼臼毒素的滞留量。结果该方法的线性范围为0．05～25ug·mL-1（r=0．9998），准确度在92．02％～101．63％之间，精密度在0．88％～4．86％之间。鬼臼毒素醇质体局部给药后能很快在离体大鼠皮肤内达到较高的药物滞留量，且维持至少12h。结论该方法快速简便，可用于大鼠皮肤中鬼臼毒素的滞留量测定。

鬼臼毒素醇质体的体外经皮渗透特性研究

目的研究鬼臼毒素醇质体经皮渗透特性。方法通过体外经皮渗透试验,比较鬼臼毒素在大鼠皮肤中的稳态透皮速率和皮肤滞留量,分别考察以醇质体、酊剂、脂质体、30%乙醇混悬液以及鬼臼毒素与空白醇质体物理混合物作为载体,鬼臼毒素经皮渗透特性。结果鬼臼毒素醇质体的12 h皮肤滞留量为8.17μg/cm2,高于其他各组;稳态透皮速率小于鬼臼毒素载药量为0.5%的脂质体组及乙醇混悬液组(P<0.05),与其他对照组无显著差异。结论醇质体具有较大的皮肤滞留量及较小的透皮速率。