Alkaloid Composition and Biological Activities of the Amaryllidaceae Species Ismene amancaes (Ker Gawl.) Herb

Pharmacological and toxicological effects of Amaryllidaceae

The Amaryllidaceae family is widely distributed in the tropics, presenting biological activity attributed mostly to alkaloids, such as an important inhibitory activity of acetylcholinesterase (AChE), antifungal, antibacterial, and cytotoxic activities. The present study aims to review the spectrum of action of the main biological activities and toxicity of secondary metabolites found in Amaryllidaceae through a literature review, using Prisma and the descriptors "Pharmacological effects of Amaryllidaceae" and "Amaryllidaceae family" and "Pharmacological actions of Amaryllidaceae", used in English and Portuguese. The literature search was done in March and May 2023. Original works published from 2012 to 2023, available in full, and presenting experimental and clinical studies were included. After the selection considering the inclusion and exclusion criteria, 60 articles fulfilled the defined criteria. From a pharmacological point of view, the highlight is due to the alkaloid galantamine, which has the potential- and is already used - for treating Alzheimer's. The toxicological aspect must be considered and evaluated carefully, as alkaloids have been associated with adverse effects such as nausea, vomiting, diarrhea, abdominal pain, and cardiovascular, neurological, and respiratory changes. Furthermore, some studies indicate that consuming these plants in significant quantities can lead to hepatic and renal toxicity. Therefore, the therapeutical use of this family's plant drugs and derivatives requires further studies to elucidate its effects and point out metabolites with therapeutic potential.

Advances on the Amaryllidacea Alkaloids Collected in South Africa, Andean South America and the Mediterranean Basin

The alkaloids are one of the most represented family of natural occurring biological active compounds. Amaryllidaceae are also very well known for their beautiful flower and are thus used as ornamental plants in historic and public gardens. The Amaryllidacea alkaloids constitute an important group that is subdivided into different subfamilies with different carbon skeletons. They are well known from ancient times for their long application in folk medicine, and in particular, Narcissus poeticus L. was known to Hippocrates of Cos (ca. B.C. 460-370), who treated uterine tumors with a formulate prepared from narcissus oil. To date, more than 600 alkaloids of 15 chemical groups exhibiting various biological activities have been isolated from the Amaryllidaceae plants. This plant genus is diffused in regions of Southern Africa, Andean South America and the Mediterranean basin. Thus, this review describes the chemical and biological activity of the alkaloids collected in these regions in the last two decades as weel those of isocarbostyls isolated from Amaryllidaceae in the same regions and same period.

Biogeographical Relationships and Diversity in the Peruvian Flora Reported by Hipólito Ruiz and José Pavón: Vegetation, Uses and Anthropology

The Royal Spanish Botanical Expedition to the Viceroyalty of Peru in the 18th century was one of the most important European expeditions to American territories. Using the herbarium sheets of Ruiz and Pavón (Royal Botanical Garden of Madrid) and their edited works, manuscripts and expedition diaries, we have constructed a database of the collected and observed flora, which has served as the basis for a map containing all of the Peruvian localities of the expedition. Based on the method of bioclimatic belts and our own observations, we have deduced to which type of vegetation the flora studied in the expedition belongs. The uses of the flora per locality were studied, as well as the ethnic groups involved in the different localities. By using a Principal Component Analysis, we have obtained the distribution of the bioclimatic belts whose vegetation was the most explored. In order to observe the bioclimatic tendency of plant uses, a Detrended Correspondence Analysis (DCA) was conducted to identify the distribution of localities with the highest frequencies of plant uses. The expedition's explorations focused on the most humid areas of the thermo- and mesotropical belts, from where a large number of plants with practical uses were obtained.

Antileishmanial Activity of Clinanthus milagroanthus S. Leiva & Meerow (Amaryllidaceae) Collected in Peru

Leishmaniasis is a worldwide infectious parasitic disease caused by different species of protozoa of the genus Leishmania, which are transmitted to animals and humans through the bite of insects of the Psychodidae family. In the present work, the antileishmanial activity of an alkaloid extract of the bulbs of Clinanthus milagroanthus S. Leiva & Meerow (Amaryllidaceae) was evaluated in vitro, in vivo, and in silico against the parasite Leishmania braziliensis, and the chemical profile of the sample was determined by GC-MS analysis. At concentrations of 1, 10, and 100 µg·mL−1, the alkaloid extract presented inhibition percentages of 8.7%, 23.1%, and 98.8%, respectively, against L. braziliensis with a p < 0.05, and IC50 values of 18.5 ± 0.3 µg·mL−1. Furthermore, at a dose of 1.0 mg·kg−1, a greater decrease in lesion size was observed (90%) for in vivo assays, as well as a decrease in infection (96%), finding no significant differences (p > 0.05) in comparison with amphotericin B (92% and 98%, respectively). Eleven alkaloids were identified in C. milagroanthus bulbs: galanthamine, vittatine/crinine, 8-O-demethylmaritidine, anhydrolycorine, 11,12-dehydroanhydrolycorine, hippamine, lycorine, 2-hydroxyanhydrolycorine, 7-hydroxyclivonine, 2α-hydroxyhomolycorine, and 7-hydroxyclivonine isomer. A molecular model of Leishmania braziliensis trypanothione reductase (TRLb) was built using computational experiments to evaluate in silico the potential of the Amaryllidaceae alkaloid identified in C. milagroanthus toward this enzyme. The structures galanthamine, 7-hydroxyclivonine isomer, and crinine showed better estimated free energy of binding than the reference compound, amphotericin B. In conclusion, this is the first in vitro, in vivo, and in silico report about the antileishmanial potential and alkaloid profiling of the extract of C. milagroanthus bulbs, which could become an interesting source of bioactive molecules.

Chemical Survey of Three Species of the Genus Rauhia Traub (Amaryllidaceae)

Plant biodiversity is an important source of compounds with medicinal properties. The alkaloid galanthamine, first isolated from Galanthus woronowii (Amaryllidaceae), is approved by the FDA for the palliative treatment of mild to moderate Alzheimer's disease due to its acetylcholinesterase (AChE) inhibitory activity. Obtaining this active pharmaceutical ingredient, still sourced on an industrial scale from the Amaryllidaceae species, is a challenge for pharmaceutical companies due to its low natural yield and the high cost of its synthesis. The aim of this work was to determine the alkaloid profile of three different Rauhia (Amaryllidaceae) species collected in Peru, and to assess the potential application of their extracts for the treatment of Alzheimer's disease. The alkaloids were identified by gas chromatography coupled to mass spectrometry (GC-MS), and the AChE inhibitory activity of the extracts was analyzed. Thirty compounds were quantified from the Rauhia species, the R. multiflora extract being the most interesting due to its high diversity of galanthamine-type structures. The R. multiflora extract was also the most active against AChE, with the half maximal inhibitory concentration (IC₅₀) values of 0.17 ± 0.02 μg·mL^-1 in comparison with the IC₅₀ values of 0.53 ± 0.12 μg·mL^-1 for galanthamine, used as a reference. Computational experiments were carried out on the activity of the galanthamine-type alkaloids identified in R. multiflora toward five different human AChE structures. The simulation of the molecules 3-O-acetylgalanthamine, 3-O-acetylsanguinine, narwedine, and lycoraminone on the 4EY6 crystal structure theoretically showed a higher inhibition of hAChE and different interactions with the active site compared to galanthamine. In conclusion, the results of this first alkaloid profiling of the Rauhia species indicate that R. multiflora is an important natural source of galanthamine-type structures and could be used as a model for the development of biotechnological tools necessary to advance the sustainable production of galanthamine.