A Novel Histological Approach for Identification of Alkaloid Bearing Plants

Metabolite profiling and histochemical localization of alkaloids in Hippeastrum papilio (Ravena) van Scheepen

Hippeastrum papilio (Amaryllidaceae) is a promising new source of galanthamine - an alkaloid used for the cognitive treatment of Alzheimer's disease. The biosynthesis and accumulation of alkaloids are tissue - and organ-specific. In the present study, histochemical localization of alkaloids in H. papilio's plant organs with Dragendorff's reagent, revealed their presence in all studied samples. Alkaloids were observed in vascular bundles, vacuoles, and intracellular spaces, while in other plant tissues and structures depended on the plant organ. The leaf parenchyma and the vascular bundles were indicated as alkaloid-rich structures which together with the high proportion of alkaloids in the phloem sap (49.3% of the Total Ion Current - TIC, measured by GC-MS) indicates the green tissues as a possible site of galanthamine biosynthesis. The bulbs and roots showed higher alkaloid content compared to the leaf parts. The highest alkaloid content was found in the inner bulb part. GC-MS metabolite profiling of H. papilio's root, bulb, and leaves revealed about 82 metabolites (>0.01% of TIC) in the apolar, polar, and phenolic acid fractions, including organic acids, fatty acids, sterols, sugars, amino acids, free phenolic acids, and conjugated phenolic acids. The most of organic and fatty acids were in the peak part of the root, while the outermost leaf was enriched with sterols. The outer and middle parts of the bulb had the highest amount of saccharides, while the peak part of the middle leaf had most of the amino acids, free and conjugated phenolic acids.

The chemistry and pharmacology of alkaloids and allied nitrogen compounds from Artemisia species: A review

Several reviews have been published on Artemisia's derived natural products, but it is the first attempt to review the chemistry and pharmacology of more than 80 alkaloids and allied nitrogen compounds obtained from various Artemisia species (covering the literature up to June 2018). The pharmacological potential and unique skeleton types of certain Artemisia's alkaloids provoke the importance of analyzing Artemisia species for bioactive alkaloids and allied nitrogen compounds. Among the various types of bioactive Artemisia's alkaloids, the main classes were the derivatives of rupestine (pyridine-sesquiterpene), lycoctonine (diterpene), pyrrolizidine, purines, polyamine, peptides, indole, piperidine, pyrrolidine, alkamides, and flavoalkaloids. The rupestine derivatives are Artemisia's characteristic alkaloids, whereas the rest are common alkaloids found in the family Asteraceae and chemotaxonomically links the genus Artemisia with the tribes Anthemideae. The most important biological activities of Artemisia's alkaloids are including hepatoprotective, local anesthetic, β-galactosidase, and antiparasitic activities; treatment of angina pectoris, opening blocked arteries, as a sleep-inducing agents and inhibition of HIV viral protease, CYP450, melanin biosynthesis, human carbonic anhydrase, [3H]-AEA metabolism, kinases, and DNA polymerase β¹ . Some of the important nitrogen metabolites of Artemisia include pellitorine, zeatin, tryptophan, rupestine, and aconitine analogs, which need to be optimized and commercialized further.

Genetic Diversity Among Saudi Peganum harmala and Rhazya stricta Populations Using Chemical and ISSR Markers

BACKGROUND

The vernacular name 'Harmal' is used for two plant species in Saudi Arabia, i.e. Peganum harmala L. and Rhazya stricta Decne. Both are important medicinal plants which offer interesting pharmacological properties.

OBJECTIVE

This study aimed to evaluate the genetic diversity among different populations of harmal based on chemical variations of alkaloids and molecular polymorphism.

METHODS

Total alkaloids were extracted from plants of three populations of each species and estimated by using spectrophotometer and the chemical compounds were analyzed by Gas chromatography mass spectrometry (GC-MS). Molecular polymorphism was estimated by using the Inter Simple Sequence Repeat (ISSR) fingerprints.

RESULTS

The results showed that the alkaloids content of R. stricta was higher than P. harmala populations. The GC-MS analysis revealed the presence of (65-53) compounds in R. stricta and P. harmala, and the percentage of polymorphism was found to be 93.2%. Sixteen ISSR primers produced 170 scorable bands with an average of 9.6 bands per primer and 75%-100% polymorphism. The cluster analysis using the unweighted pair-group method of the arithmetic average (UPGMA) method based on combined data of GC-MS and ISSR markers divided the six harmal genotypes into two major groups.

CONCLUSION

The existence of variations in chemical and genetic markers is useful for the selection of potential genotypes for medicinal use, and for breeding lines for medicinal substances production to spare wild plants from uncontrolled harvesting for folk medicine.