Sample sites with two ephedrine-type alkaloids.

Ephedra sinica Stapf. is a shrubby plant widely used in traditional Chinese medicine due to its high level of medicinal value, thus, it is in high demand. Ephedrine (E) and pseudoephedrine (PE) are key medicinal components and quality indicators for E. sinica. These two ephedrine-type alkaloids are basic elements that exert the medicinal effect of E. sinica. Recently, indiscriminate destruction and grassland desertification have caused the quantity and quality of these pharmacological plants to degenerate. Predicting potentially suitable habitat for high-quality E. sinica is essential for its future conservation and domestication. In this study, MaxEnt software was utilized to map suitable habitats for E. sinica in Inner Mongolia based on occurrence data and a set of variables related to climate, soil, topography and human impact. The model parametrization was optimized by evaluating alternative combinations of feature classes and values of the regularization multiplier. Second, a geospatial quality model was fitted to relate E and PE contents to the same environmental variables and to predict their spatial patterns across the study area. Outputs from the two models were finally coupled to map areas predicted to have both suitable conditions for E. sinica and high alkaloid content. Our results indicate that E. sinica with high-quality E content was mainly distributed in the Horqin, Ulan Butong and Wulanchabu grasslands. E. sinica with high-quality PE content was primarily found in the Ordos, Wulanchabu and Ulan Butong grasslands. This study provides scientific information for the protection and sustainable utilization of E. sinica. It can also help to control and prevent desertification in Inner Mongolia.

草麻黄（Ephedra sinica Stapf.）是一种灌木状植物，因其极高的药用价值而广泛应用于中医药领域，市场需求居高不下。麻黄碱（Ephedrine, E）与伪麻黄碱（Pseudoephedrine, PE）是草麻黄的核心药用成分与质量评价指标，这两类麻黄类生物碱是草麻黄发挥药效的物质基础。近年来，无节制采挖与草地荒漠化导致该药用植物的资源储量与品质均出现退化。精准预测优质草麻黄的潜在适宜生境，对其后续保护与引种驯化工作至关重要。
本研究基于物种出现数据（occurrence data），结合气候、土壤、地形与人类活动影响等多组环境变量，利用MaxEnt软件对内蒙古地区草麻黄的适宜生境开展制图分析。通过评估特征类别与正则化乘数（regularization multiplier）的不同组合及取值，优化了模型参数设置。
其次，本研究构建了地理空间质量模型，将麻黄碱与伪麻黄碱含量与上述环境变量进行关联分析，并预测了研究区内二者的空间分布格局。最终将两个模型的输出结果进行耦合，绘制出同时满足草麻黄适宜生境与高生物碱含量的区域。
研究结果显示，高麻黄碱含量的草麻黄主要分布于科尔沁草原、乌兰特布草原与乌兰察布草原；高伪麻黄碱含量的草麻黄则主要集中于鄂尔多斯草原、乌兰察布草原与乌兰特布草原。
本研究为草麻黄的保护与可持续利用提供了科学依据，同时也可为内蒙古地区的荒漠化防治工作提供参考。