Fern constituent: Naturally occurring adian-5-ene ozonide in the leaves of and

An overview on the antimalarial activity of 1,2,4-trioxanes, 1,2,4-trioxolanes and 1,2,4,5-tetraoxanes

The demand for novel, fast-acting, and effective antimalarial medications is increasing exponentially. Multidrug resistant forms of malarial parasites, which are rapidly spreading, pose a serious threat to global health. Drug resistance has been addressed using a variety of strategies, such as targeted therapies, the hybrid drug idea, the development of advanced analogues of pre-existing drugs, and the hybrid model of resistant strains control mechanisms. Additionally, the demand for discovering new potent drugs grows due to the prolonged life cycle of conventional therapy brought on by the emergence of resistant strains and ongoing changes in existing therapies. The 1,2,4-trioxane ring system in artemisinin (ART) is the most significant endoperoxide structural scaffold and is thought to be the key pharmacophoric moiety required for the pharmacodynamic potential of endoperoxide-based antimalarials. Several derivatives of artemisinin have also been found as potential treatments for multidrug-resistant strain in this area. Many 1,2,4-trioxanes, 1,2,4-trioxolanes, and 1,2,4,5-tetraoxanes derivatives have been synthesised as a result, and many of these have shown promise antimalarial activity both in vivo and in vitro against Plasmodium parasites. As a consequence, efforts to develop a functionally straight-forward, less expensive, and vastly more effective synthetic pathway to trioxanes continue. This study aims to give a thorough examination of the biological properties and mode of action of endoperoxide compounds derived from 1,2,4-trioxane-based functional scaffolds. The present system of 1,2,4-trioxane, 1,2,4-trioxolane, and 1,2,4,5-tetraoxane compounds and dimers with potentially antimalarial activity will be highlighted in this systematic review (January 1963-December 2022).

Impallidane skeleton as a novel triterpenoid methyl ether from rhizomes of Imperata cylindrica var. koenigii f. pallida

ABSTRUCT: n-Hexane extract of rhizomes of Imperata cylindrica var. koenigii f. pallida yielded five novel skeletal triterpenoids, designed as impallidin (1), impallidol (2), impallidin ozonide (3a, 3b), trisnorimpallidin aldehyde (4), tetranorimpallidin aldehyde (5). Structures of novel compounds were elucidated by mainly 2D NMR and other spectroscopic analysis and chemical correlations. Alternatively, compound 3a, 3b was derivatized from 1 under ozone oxidation condition.

Antiprotozoal and Antitumor Activity of Natural Polycyclic Endoperoxides: Origin, Structures and Biological Activity

Polycyclic endoperoxides are rare natural metabolites found and isolated in plants, fungi, and marine invertebrates. The purpose of this review is a comparative analysis of the pharmacological potential of these natural products. According to PASS (Prediction of Activity Spectra for Substances) estimates, they are more likely to exhibit antiprotozoal and antitumor properties. Some of them are now widely used in clinical medicine. All polycyclic endoperoxides presented in this article demonstrate antiprotozoal activity and can be divided into three groups. The third group includes endoperoxides, which show weak antiprotozoal activity with a reliability of up to 70%, and this group includes only 1.1% of metabolites. The second group includes the largest number of endoperoxides, which are 65% and show average antiprotozoal activity with a confidence level of 70 to 90%. Lastly, the third group includes endoperoxides, which are 33.9% and show strong antiprotozoal activity with a confidence level of 90 to 99.6%. Interestingly, artemisinin and its analogs show strong antiprotozoal activity with 79 to 99.6% confidence against obligate intracellular parasites which belong to the genera Plasmodium, Toxoplasma, Leishmania, and Coccidia. In addition to antiprotozoal activities, polycyclic endoperoxides show antitumor activity in the proportion: 4.6% show weak activity with a reliability of up to 70%, 65.6% show an average activity with a reliability of 70 to 90%, and 29.8% show strong activity with a reliability of 90 to 98.3%. It should also be noted that some polycyclic endoperoxides, in addition to antiprotozoal and antitumor properties, show other strong activities with a confidence level of 90 to 97%. These include antifungal activity against the genera Aspergillus, Candida, and Cryptococcus, as well as anti-inflammatory activity. This review provides insights on further utilization of polycyclic endoperoxides by medicinal chemists, pharmacologists, and the pharmaceutical industry.

Exploration of artemisinin derivatives and synthetic peroxides in antimalarial drug discovery research

Malaria is a life-threatening infectious disease caused by protozoal parasites belonging to the genus Plasmodium. It caused an estimated 405,000 deaths and 228 million malaria cases globally in 2018 as per the World Malaria Report released by World Health Organization (WHO) in 2019. Artemisinin (ART), a "Nobel medicine" and its derivatives have proven potential application in antimalarial drug discovery programs. In this review, antimalarial activity of the most active artemisinin derivatives modified at C-10/C-11/C-16/C-6 positions and synthetic peroxides (endoperoxides, 1,2,4-trioxolanes, 1,2,4-trioxanes, and 1,2,4,5-tetraoxanes) are systematically summarized. The developmental trend of ART derivatives, and cyclic peroxides along with their antimalarial activity and how the activity is affected by structural variations on different sites of the compounds are discussed. This compilation would be very useful towards scaffold hopping aimed at avoiding the unnecessary complexity in cyclic peroxides, and ultimately act as a handy resource for the development of potential chemotherapeutics against Plasmodium species.

Ethnopharmacological uses, phytochemistry and pharmacology of genus Adiantum: A comprehensive review

ETHNOPHARMACOLOGICAL RELEVANCE

Genus Adiantum (Pteridaceae) forms a significant dominant component of many plant communities especially in the tropical and temperate regions. These are commonly known as maidenhair ferns and several have been used medicinally in different parts of the world. They exhibit antidysenteric, antiulcer, antimicrobial, antitumor and antiviral activities. The traditional uses of Adiantum species are known to be for respiratory problems such as cough cold, fever, pneumonia and mucous formation.

AIM OF THE REVIEW

This review aims to provide a comprehensive and updated, categorized information on the botanical aspects, traditional uses, phytochemistry, pharmacological activities and toxicological research of Adiantum species in order to explore their therapeutic potential and evaluate future research opportunities.

MATERIALS AND METHODS

The available information on various species belonging to the genus Adiantum was collected via electronic search (using Pubmed, SciFinder, Scirus, Google Scholar, JCCC@INSTIRC and Web of Science) and a library search for articles published in peer-reviewed journals.

RESULTS

The literature provided information on several ethnopharmacologically well known Adiantum species, the best studied species being A. capillus-veneris. From these plant species, more than 130 compounds belonging to triterpenoids, flavanoids, phenyl propanoids, phenolics, coumarins, phytosterols, fatty acids and others were identified. Experimental evidences confirmed that the Adiantum species could be used in treating microbial infections, diabetes, liver disorders as well as inflammatory disorders.

CONCLUSIONS

Plants belonging to the genus Adiantum have offered bioactive crude extracts as well as pure compounds, thus substantiating their effectiveness in traditional medicine. Although toxicity studies carried out on some Adiantum species have showed them to be non-toxic, further toxicological studies are still required to confirm their safety in humans. Future research should be directed towards implementing an integrated approach through intensive investigations of all the species of Adiantum relating to phytochemical and pharmacological properties, especially bio-assay guided isolation of phytoconstituents, their mechanism of action, as well as their bioavailability and pharmacokinetics, safety and efficacy.

A novel 3,9-(1,2,3-trioxocine)-type steroid of Rauia nodosa (Rutaceae)

A new natural product, a 3,9-(1,2,3-trioxocine)-type steroid, named rauianodoxy (6), was isolated from Rauia nodosa, together with five steroids: sistostenone (1), stigmastenone (2), sitosterol (3), stigmasterol (4) and ergosterol peroxide (5), one coumarin, O-geranylosthenol (7), and three alkaloids, N-methylflindersine (8), zantobungeanine (9) and veprissine (10). Compounds 5–8 were isolated for the first time in the genus Rauia. These compounds were characterized on the basis of their spectral data, mainly one and two-dimensional NMR, and mass spectra, also involving comparison with the literature data. Theoretical studies at the DFT level reveal structural parameters for the 1,2,3-trioxole bridge compatible with known structures containing a similar group.

Triterpene compounds isolated from Acer mandshuricum and their anti-inflammatory activity

In our preliminary screening study on the anti-inflammatory activity, a new triterpene compound, aceranol acetate (1), was isolated along with five known compounds: beta-amyrin acetate (2); glutinol acetate (3); friedelin (4); glutinol (5); (3beta)-d-glucopyranoside-stigmast-5-en-3-yl (6), from the stems and leaves of Acer mandshuricum. The structure of the new triterpene was determined to be 5alpha,6alpha-epidioxy-5beta,6beta-epoxy-9,13-dimethyl-25,26-dinoroleanan-3beta-ol acetate by spectroscopic studies. Compounds 2-6 were isolated from this plant for the first. Five triterpene compounds (1-5) showed significant cytotoxic activity with GI(50) in the range of 11.1-17.9microM, whereas steroid compound (6) exhibited moderate activity against four human cancer cell lines (HL-60, SK-OV-3, A549, and HT-29). Furthermore, the anti-inflammatory effects of compounds 1-6 in the non-cytotoxic concentrations (1-100nM) were evaluated for the inhibitory activity of TNF-alpha secretion in the lipopolysaccharide (LPS)-stimulated murine RAW264.7 macrophage cell line. Among the compounds tested, compound 2 showed the strongest anti-inflammatory activity with the inhibition rate up to 38.40% at the concentration of 100nM, whereas other five compounds (2-6) exhibited moderate activity.