摘要
According to the Chinese Pharmacopoeia,the Chinese medicinal material(Asari Radix et Rhizoma)Xixin is derived from the species Asarum heterotropoides var.mandshuricum,A.sieboldii,and A.sieboldii var.seoulense.However,many species of the genus Asarum are labeled as"Xixin","Tu-Xixin",or"Nan-Xixin"for sale in producing areas.To distinguish Chinese Asarum species and to ensure their safety and efficacy,we examined the microscopic characteristics of subg.Asarum plants in China(including subg.Asarum plants in the classification system of Flora Reipublicae Popularis Sinicae and the later published Asarum yunnanense)using a hand microtome and a microscopic digital imaging system based on our previous research.Microscopic features of the blades,petioles,and roots of A.yunnanense were investigated for the first time.Moreover,we compared nine species and one variety of the subg.Asarum(i.e.,A.yunnanense,A.caudigerellum,A.himalaicum,A.pulchellum,A.debile,A.caulescens,A.renicordatum,A.caudigerum,A.caudigerum var.cardiophyllum and A.geophilum)in China based on microscopic characteristics of the blades.Several parameters,such as morphological characteristics and distribution of hairs on both upper and lower leaf epidermises;morphological characteristics of hair cells;anticlinal walls of lower epidermal cells;size relationship between outer periclinal walls and cavity outlines of oil cells on lower leaf epidermis;presence or absence of the irregular cells containing red to brown substances among mesophyll cells;and the diameter of the largest vessels in midribs of the blades,were used for discrimination among species.To the best of our knowledge,we provided the first identification key for the 10 taxa based on blade microscopic characteristics that could be used to distinguish these taxa.Based on the key,23 commercial samples collected from seven provinces of China were authenticated as whole dried herbs of A.himalaicum,A.caudigerellum,A.caudigerum,A.pulchellum and A.caulescens.These findings indicated that microscopic approach and related techniques were convenient and feasible and could be used for the authentication of crude drugs from Chinese subg.Asarum species.
2015版《中国药典》规定细辛来源于马兜铃科细辛属植物北细辛Asarumheterotropoides var.mandshuricum、汉城细辛A.sieboldii var.seoulense和华细辛Asarum sieboldii干燥的根和根茎。然而,同属的很多种被当作"细辛"、"土细辛"或者"南细辛"在产地出售使用。为了准确鉴别细辛类药材,确保它们的安全和有效,在本研究室工作的基础上,采用手持切片器制片和显微数码成像等技术方法,首次对云南细辛组织构造进行了显微鉴定研究,包括对云南细辛叶片、叶柄和根的组织构造特征进行了详细的观测和描述;并系统比较了中国产细辛亚属(《中国植物志》系统及后来发表的云南细辛)除台湾细辛之外的9种及1变种的叶表面显微特征。结果表明叶片上、下表面非腺毛的形态和分布、毛细胞形态、下表皮细胞垂周壁的弯曲程度、油细胞胞腔和外平周壁的大小关系、叶肉细胞有无红色或褐色物质、叶片主脉维管束中最大导管直径等特征对于细辛亚属10个类群的鉴定具有重要的意义;依据叶片的显微特征建立了这10个类群的鉴别检索表;依据检索表,鉴别了市场上常见的细辛亚属商品主要是单叶细辛和短尾细辛的全草。研究显示,显微鉴定是一种方便的、可行的技术,可用于鉴别来源于中国产细辛亚属的药材。
