Pharmacognostical study of Sterculia monosperma fruit

Abstract

Sterculia monosperma fruit is the dried and mature seed of Sterculia monosperma, which belongs to genus Sterculia. In China, this plant is a widely distributed arbor with a long planting history in Lingnan area. It is mainly cultivated in Guangdong, Guangxi, Fujian, Yunnan and Taiwan of China; it is also distributed in India, Vietnam and Indonesia, mostly cultivated artificially. S. monosperma fruit has many functions like warming the stomach and killing pests, but its name and characteristics are easily confused with other plants of genus Sterculia. However, the relevant research foundation is relatively weak. Pharmacognostical study can provide reference for its resource development and quality standard formulation. This study identifies the morphological and microscopic characteristics of S. monosperma fruit, as well as the microscopic identification of seed cross-section and powder. The DNA barcode sequences ITS2, psbA-trnH, matK and rbcL of S. monosperma were obtained through bidirectional sequencing, Kimura 2-Parameter (K2P) genetic distance was calculated, and the neighbor joining tree was established for clustering analysis. The results were as follows: (1) The morphological characteristics of S. monosperma fruit included dark red fruit shell and reddish brown or dark chestnut surface. It was hard in texture, with two thick yellowish endosperms inside. (2) The micro-morphological characteristics was that the exotesta was reddish brown, extremely thin, and brittle in texture; the mesotesta was black brown, thick, and hard in texture; the endotesta coat was light yellow and soft in texture. (3) The microscopic characteristics included the structure and arrangement of the exotesta stone cell, the grid cell structure of the mesotesta, the bead thickening of the cell wall of the endotesta cells, and the calcium oxalate cluster crystals. (4) Based on the ITS2 sequence, S. monosperma fruit could be effectively distinguished from other plants in genus Sterculia, while the matK sequence could effectively distinguish S. lanceolata from other plants in genus Sterculia. This study obtained the data on the morphological characteristics, micro-morphological characteristics and microscopic characteristics of S. monosperma fruit. Combined with the ITS2 barcode sequence, S. monosperma fruit can be effectively identified, which provides a scientific reference for the development of its germplasm resources and the formulation of relevant quality standards.

Keywords

• sterculia monosperma fruit
• morphological identification
• micro-morphological identification
• microscopic identification
• dna barcode