Lycorine derivatives against Trichomonas vaginalis

Identification of the Constituents in Cnidii Fructus Active Against Trichomonas vaginalis Parasites

Ethanol extracts of Cnidii Fructus, the dried fruits of Cnidium monnieri (L.) Cusson, have been externally applied in the treatment of Trichomonas vaginalis. However, the precise identity of the major constituents responsible for activity against T. vaginalis is unknown, but there is probability they are coumarin derivatives. In this study, the anti-Trichomonas activity of 4 major coumarin derivative constituents of Cnidii Fructus, namely, osthole, xanthotoxin, isopimpinellin, and bergapten, was characterized in terms of the resulting kinetics of growth and morphology of T. vaginalis upon treatment. The results demonstrated that osthole and xanthotoxol had significant trichomonacidal ability, while isopimpinellin and bergapten displayed low or no inhibitory efficacy toward T. vaginalis parasites. Our study suggests that the coumarin derivatives osthole and xanthotoxol can be potentially used as a basis for the development and design of new drugs for application in alternative or synergistic therapy against T. vaginalis.

Antiproliferative Effects of Alkaloids from the Bulbs of Crinum abyscinicum Hochst. ExA. Rich

Crinum abyscinicum Hochst. ExA. Rich bulb is traditionally used in Ethiopia for the treatment of various ailments including internal parasites, mastitis, rabies, colic diseases of animals, and cancer. Despite its importance in traditional cancer treatment, no research work has been reported on the antiproliferative activity of the bulb extract and its major constituents. Phytochemical investigation of the bulb extract of C. abyscinicum by PTLC over silica gel resulted in the isolation of two alkaloids, which were unequivocally identified as 6-hydroxycrinamine and lycorine on the basis of ¹H- and ¹³C-NMR and MS analysis. The bulb extract, 6-hydroxycrinamine, and lycorine possessed significant antiproliferative activity, lycorine being the most active exhibiting GI₅₀ values of 2.8 μg/ml and 3.4 μg/ml against A2780 and MV4-11 cells, respectively. Cell cycle analysis and annexin V/propidium iodide double staining in A2780 cells revealed that both compounds increased the percentage of cells in the S-phase at 30 μg/ml without inducing apoptosis. Our results suggest that the antiproliferative activities of the bulb extract of C. abyscinicum, 6-hydroxycrinamine, and lycorine could support the traditional claim of the plant against cancer.

Anti-trichomonad activities of different compounds from foods, marine products, and medicinal plants: a review

Human trichomoniasis, caused by the pathogenic parasitic protozoan Trichomonas vaginalis, is the most common non-viral sexually transmitted disease that contributes to reproductive morbidity in affected women and possibly to prostate cancer in men. Tritrichomonas foetus strains cause the disease trichomoniasis in farm animals (cattle, bulls, pigs) and diarrhea in domestic animals (cats and dogs). Because some T. vaginalis strains have become resistant to the widely used drug metronidazole, there is a need to develop alternative treatments, based on safe natural products that have the potential to replace and/or enhance the activity of lower doses of metronidazole. To help meet this need, this overview collates and interprets worldwide reported studies on the efficacy of structurally different classes of food, marine, and medicinal plant extracts and some of their bioactive pure compounds against T. vaginalis and T. foetus in vitro and in infected mice and women. Active food extracts include potato peels and their glycoalkaloids α-chaconine and α-solanine, caffeic and chlorogenic acids, and quercetin; the tomato glycoalkaloid α-tomatine; theaflavin-rich black tea extracts and bioactive theaflavins; plant essential oils and their compounds (+)-α-bisabolol and eugenol; the grape skin compound resveratrol; the kidney bean lectin, marine extracts from algae, seaweeds, and fungi and compounds that are derived from fungi; medicinal extracts and about 30 isolated pure compounds. Also covered are the inactivation of drug-resistant T. vaginalis and T. foetus strains by sensitized light; anti-trichomonad effects in mice and women; beneficial effects of probiotics in women; and mechanisms that govern cell death. The summarized findings will hopefully stimulate additional research, including molecular-mechanism-guided inactivations and human clinical studies, that will help ameliorate adverse effects of pathogenic protozoa.

Antiprotozoal alkaloid principles of the plant family Amaryllidaceae

Protozoan-borne diseases are prominent amongst diseases caused by parasites. Given their alarming morbidity and mortality statistics, there is ever growing interest in new therapies against these diseases. Whilst synthetic drugs such as benznidazole and melarsoprol have had a profound influence on the clinical setup, there has been significant interest in the phytochemical platform to also deliver such drug candidates. The plant family Amaryllidaceae is recognizable for its isoquinoline alkaloids, which exhibit attractive molecular architectures and interesting biological properties. This survey focuses on the antiprotozoal activities of 73 of such substances described in 18 different species of the Amaryllidaceae. Of these, 2-O-acetyllycorine was identified as the most potent (IC₅₀ 0.15 μg/mL against Trypansoma brucei brucei). Also considered are structure-activity relationships which have served to modulate activities, as well as the plausible mechanisms that underpin these effects and afford insight to the Amaryllidaceae alkaloid antiprotozoal pharmacophore.

Lycorine: A prospective natural lead for anticancer drug discovery

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Outline of the anticancer properties and associated molecular mechanism mediated by lycorine.

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Comprehensive analysis of the structure activity relationship associated with anticancer activity of lycorine.

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Summary of the pharmacological aspects and implications for future directions with this compound.

Nature is the most abundant source for novel drug discovery. Lycorine is a natural alkaloid with immense therapeutic potential. Lycorine is active in a very low concentration and with high specificity against a number of cancers both in vivo and in vitro and against various drug-resistant cancer cells. This review summarized the therapeutic effect and the anticancer mechanisms of lycorine. At the same time, we have discussed the pharmacology and comparative structure-activity relationship for the anticancer activity of this compound. The researches outlined in this paper serve as a foundation to explain lycorine as an important lead compound for new generation anticancer drug design and provide the principle for the development of biological strategies to utilize lycorine in the treatment of cancers.

Hippeastrum reticulatum (Amaryllidaceae): Alkaloid Profiling, Biological Activities and Molecular Docking

The Amaryllidaceae family has proven to be a rich source of active compounds, which are characterized by unique skeleton arrangements and a broad spectrum of biological activities. The aim of this work was to perform the first detailed study of the alkaloid constituents of Hippeastrum reticulatum (Amaryllidaceae) and to determine the anti-parasitological and cholinesterase (AChE and BuChE) inhibitory activities of the epimers (6α-hydroxymaritidine and 6β-hydroxymaritidine). Twelve alkaloids were identified in H. reticulatum: eight known alkaloids by GC-MS and four unknown (6α-hydroxymaritidine, 6β-hydroxymaritidine, reticulinine and isoreticulinine) by NMR. The epimer mixture (6α-hydroxymaritidine and 6β-hydroxymaritidine) showed low activity against all protozoan parasites tested and weak AChE-inhibitory activity. Finally, a molecular docking analysis of AChE and BuChE proteins showed that isoreticulinine may be classified as a potential inhibitory molecule since it can be stabilized in the active site through hydrogen bonds, π-π stacking and hydrophobic interactions.

Recent developments in anti-Trichomonas research: An update review

Trichomonas vaginalis is a major non-viral sexually-transmitted infection resulted into serious obstetrical and gynecological troubles. The increasing resistance to nitroimidazole therapy and recurrence makes it crucial to develop new drugs against trichomoniasis. Over the past few years, a large number of research articles highlighting the synthetic and natural product research to combat Trichomonas vaginalis have been published. Electronic databases were searched to collect all data from the year 2006 through June 2017 for anti-Trichomonas activity potential of synthetic and natural products. This review article put together the synthetic and natural product research to find out an effective metronidazole alternative to cure trichomoniasis.

Natural and synthetic compound anti-Trichomonas vaginalis: an update review

Trichomonas vaginalis is a flagellate protozoan that causes trichomonosis, a sexually transmitted disease of worldwide importance. However, the infection has long received much less attention than other parasitic and sexually transmitted diseases. This negligence leads to poor diagnosis and underestimated prevalence values, and consequently, it has been associated to increasing acquisition and transmission of HIV, pregnancy outcomes, infertility, pelvic inflammatory disease, and cervical and prostate cancer. In view of increased resistance to drugs belonging to the nitroimidazole class, new treatment alternatives are urgently needed. Natural products provide an immeasurable wealth of active molecules, and a great number of new drugs have been originated from these compounds. In addition, new synthetic products or derivatives from old drugs also provide an alternative to treat trichomonosis. Albeit many studies have been performed with natural products against T. vaginalis, none of them progressed to clinical trials. Overall, inadequate financial investments are made, and no alternative treatment for trichomonosis has been discovered; meanwhile, hundreds of thousands of people will remain infected and suffering the serious consequences of this nonviral STD. Thus, it is highlighted that clinical trials for better understanding the potential in vitro are necessary and urgent in order to furnish a new therapeutic alternative for trichomonosis treatment. The current review attempts to give an overview on the potential of natural and synthetic products as antitrichomonal.

Biological and pharmacological activities of amaryllidaceae alkaloids

This review discusses the recent developments on biological and pharmacological activities of amaryllidaceae alkaloids with IC₅₀or EC₅₀values since 2005, supporting the potential therapeutic possibilities for the use of these compounds.

Drug library screening against metronidazole-sensitive and metronidazole-resistant Trichomonas vaginalis isolates

OBJECTIVES

Metronidazole and tinidazole are effective treatments for most patients with trichomoniasis but not for individuals who are infected with very resistant strains of Trichomonas vaginalis or persons with hypersensitivity to the 5-nitroimidazole drugs. Thus, there is a need for additional oral therapies to treat trichomoniasis.

METHODS

We screened the US Drug Collection Library against metronidazole-susceptible and resistant strains of T vaginalis. Activity was measured by incubating parasites and drugs for 48 h in the presence of tritiated thymidine. Growth inhibition was determined by the reduction of incorporated radioactivity by compounds at 20 μM in comparison to media control. Drugs that showed good initial activity were further tested to calculate IC50 values. Drugs with the most promise were tested together with metronidazole to see if there was any combinatorial effect.

RESULTS

Of the 1040 drugs in the library, 83 (8%) reduced growth of a metronidazole-susceptible T vaginalis strain by at least 20%. Of these, IC50 values were calculated for 27 compounds and 8 drugs were evaluated in combination with metronidazole. Disulfiram and nithiamide were non-5-nitroimidazole drugs that showed the best activity against parasites when used alone. Albendazole and coenzyme B12 were the most promising compounds to boost the efficacy of metronidazole.

CONCLUSIONS

No one drug was as effective as any of the 5-nitroimidazole compounds. However, disulfiram and nithiamide may be useful to treat individuals with hypersensitivity to 5-nitroimidazole drugs and albendazole and coenzyme B12 may be helpful in combination with metronidazole or tinidazole for treatment of persons with highly resistant T vaginalis infections.

Amaryllidaceae and Sceletium alkaloids

Covering: July 2010 to June 2012. Previous review: Nat. Prod. Rep., 2011, 28, 1126-1142. Recent progress on the isolation, identification, biological activity and synthetic studies of structurally diverse alkaloids from plants of the family Amaryllidaceae is summarized in this review. In addition, the structurally related alkaloids isolated from Sceletium species are discussed as well.

Towards a molecular understanding of the biosynthesis of amaryllidaceae alkaloids in support of their expanding medical use

The alkaloids characteristically produced by the subfamily Amaryllidoideae of the Amaryllidaceae, bulbous plant species that include well know genera such as Narcissus (daffodils) and Galanthus (snowdrops), are a source of new pharmaceutical compounds. Presently, only the Amaryllidaceae alkaloid galanthamine, an acetylcholinesterase inhibitor used to treat symptoms of Alzheimer's disease, is produced commercially as a drug from cultivated plants. However, several Amaryllidaceae alkaloids have shown great promise as anti-cancer drugs, but their further clinical development is restricted by their limited commercial availability. Amaryllidaceae species have a long history of cultivation and breeding as ornamental bulbs, and phytochemical research has focussed on the diversity in alkaloid content and composition. In contrast to the available pharmacological and phytochemical data, ecological, physiological and molecular aspects of the Amaryllidaceae and their alkaloids are much less explored and the identity of the alkaloid biosynthetic genes is presently unknown. An improved molecular understanding of Amaryllidaceae alkaloid biosynthesis would greatly benefit the rational design of breeding programs to produce cultivars optimised for the production of pharmaceutical compounds and enable biotechnology based approaches.