Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut 06269-3043, USA.
Pharm Biol. 2012 Mar;50(3):384-92. doi: 10.3109/13880209.2011.608077. Epub 2011 Nov 25.
Presence/absence tests for alkaloids of 31 medicinal vascular plant species from 31 genera and 26 families of eastern Nicaragua provided a baseline for bioactivity tests.
To determine the bioactivity and cytoxicity of aqueous extracts of widely used medicinal species in eastern Nicaragua.
Ethnomedicinal applications were obtained from interviews of traditional healers. We used Dragendorff's reagent to test alkaloids and brine shrimp for cytotoxicity of aqueous extracts.
Twenty-nine of the 31 species tested positive for alkaloids. The median lethal concentration that kills 50% of the larvae within 24 h of contact with the extract (LC(50) was less than 1000 µg/mL for 4 (13%) species (the usual cytotoxic category), 1001-5000 µg/mL for 23 (74%) species, and between 5001-7500 µg/mL for the remaining 4 (13%) species.
Twenty-five of the ethnomedicines contain alkaloids but are not cytotoxic. In contrast to first suppositions, we suggest that this is a good and desirable, and perhaps expected, outcome. Medicinal plants that are cytotoxic may obviously control or kill bacteria or other pathogens, but may also negatively affect the patient; some high alkaloid levels have been associated with carcinogens. Thus, perhaps the majority of effective medicinals should be expected to be noncytotoxic. We suggest that this is a new paradigm for consideration of the overall value and effectiveness of medicinals. Of course, medicinals also can be effective in numerous ways (e.g., organ stimulation or other physiological functions) other than simply as antimicrobials or antipathogens.
对来自尼加拉瓜东部 31 个属和 26 个科的 31 种药用维管植物的生物碱进行有无检测，为生物活性检测提供了基线。
测定尼加拉瓜东部广泛使用的药用物种的水提物的生物活性和细胞毒性。
从传统治疗师的访谈中获得民族医学应用。我们使用 Dragendorff 试剂检测生物碱和盐水虾的水提物的细胞毒性。
在所测试的 31 种物种中，有 29 种呈生物碱阳性。在接触提取物 24 小时内杀死 50%幼虫的半数致死浓度（LC50）小于 1000µg/mL 的有 4 种（13%）（通常的细胞毒性类别），1001-5000µg/mL 的有 23 种（74%），其余 4 种（13%）在 5001-7500µg/mL 之间。
25 种民族药物含有生物碱但无细胞毒性。与最初的假设相反，我们认为这是一个良好且理想的结果，也许是可以预料到的。细胞毒性的药用植物显然可以控制或杀死细菌或其他病原体，但也可能对患者产生负面影响；一些高生物碱水平与致癌物质有关。因此，也许大多数有效的药用植物应该是非细胞毒性的。我们建议，这是一个考虑药用植物整体价值和有效性的新范式。当然，药用植物也可以通过许多方式（例如器官刺激或其他生理功能）发挥作用，而不仅仅是作为抗菌剂或抗病原体。
