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Heterocyclic Drugs from Plants
Published in Rohit Dutt, Anil K. Sharma, Raj K. Keservani, Vandana Garg, Promising Drug Molecules of Natural Origin, 2020
Debasish Bandyopadhyay, Valeria Garcia, Felipe Gonzalez
Simalikalactone D (or SkD) (Figure 8.22) is a quassinoid that is isolated from the plants Quassia amara and Quassia africana (Simalikalactone, 2018). This compound is an antimalarial, cytotoxic, and antiviral. As an anti-malarial SkD attacks the life cycle of plasmodia if the host is human. Quassia amara is widely used for its antimalarial activity when it is even taken just as a tonic. This traditional antimalarial remedy showed excellent in vitro and in vivo activities (Bertani et al., 2006). Even the water extract of the freshly crushed leaves of the plant Quassia amara showed excellent antiplasmodial activity (Suh et al., 2004). The active principle of this extract, which is SkD, synergizes in vitro with atovaquone against Plasmodium falciparum. SkD (45 nM concentration) is noxious for mid-trophozoite P. falciparum, and the SkD and atovaquone combination acts upon the mitochondria of P. falciparum (Bertani et al., 2012). Another compound quassinoids malika lactone E (SkE), repressed the growth of P. falciparum culture in vitro by 50%, in the concentration range from 24 to 68 nM, independently of the strain sensitivity to chloroquine (Cachet et al., 2009). Both SkE and SkD showed promising efficacy against malignant malaria.
Epstein–Barr Virus and Treatment of Its Infection
Published in Satya Prakash Gupta, Cancer-Causing Viruses and Their Inhibitors, 2014
Tarun Jha, Amit Kumar Halder, Nilanjan Adhikari
Some clauslactones were isolated from the leaves of Clausena excavate belonging to the family Rutaceae by Ito et al. (2000a). Among these, clauslactone C (94, Figure 6.11) was observed to be the most potent compound. Carbazole alkaloids were also isolated by Ito et al. (2000b) from Clausena anisata belonging to the family Rutaceae. One compound—ekeberginine (95, Figure 6.11)—was found to be the most potent while others also showed potent inhibitory activity against EBV-EA activation. Compound 96 (Figure 6.11) was found to be the most potent depsidone from Garcinia assigu (family: Guttiferae) (Ito et al. 2001). Tamura et al. (2002) synthesized seven shinjulactone C (quassinoid isolated from Ailanthus altissima) derivatives and evaluated their antitumor-promoting effects against EBV-EA. Among these synthetic derivatives, compound 97 (Figure 6.11), having a 3′, 3′-dimethylsuccinate moiety, showed the highest inhibition. A SAR study suggested that succinate derivatives have better activity than glutarates. Some diterpene compounds were isolated from the cones of Pinus luchuensis (family: Pinaceae) by Minami et al. (2002), and 15-nor-14-oxolabda-8(17)-12E-dien-19-oic acid (98, Figure 6.11) exhibited the highest activity. Some sarcophine analogs were also tested against EBV-EA by Katsuyama et al. (2002) where some compounds showed higher chemopreventive activity; the highest activity was associated with 99 (Figure 6.11). Some xanthones were isolated from the stem bark of Calophyllum brasilienses (family: Guttiferae) by Ito et al. (2002). Some of these compounds showed promising inhibitory activity against TPA-induced EBV-EA activation in Raji cells, and brasixanthone B (100, Figure 6.11) was found to be the most potent.
Exploring the potential of solid dispersion for improving solubility, dissolution & bioavailability of herbal extracts, enriched fractions, and bioactives
Published in Journal of Microencapsulation, 2021
Debadatta Mohapatra, Ashish K. Agrawal, Alakh N. Sahu
Eurycoma longifolia Jack (Family-Simaroubaceae) roots extract is widely used as an additive in food beverages, marketed for their aphrodisiac use & improvement of male libido. The bitter principle of the root (quassinoids), mainly eurycomanone (EN) & 13 α (21)-epoxyeurycomanone (EP) are responsible for testosterone production, enhancing spermatogenesis and fertility. However, due to the high aqueous solubility of quassinoids, the lipid membrane permeability is the rate-limiting step for oral absorption & bioavailability. Ma et al. developed lipid-based SD of root extract fraction (TAF2) using a combination of Gelucire G44/14 & hydrophobic surfactant Span 60 via melt–fusion method. The lipid-based SD was found to increase the permeability of quassinoids & a significant increase in sperm count than the vehicle-treated and neat standardised TAF2 group (Ma et al.2017). In another work, the authors also investigated intestinal absorption, oral pharmacokinetic profile, and bioavailability in male Sprague-Dawley rats. Significant improvement in intestinal absorption and oral bioavailability was observed with lipid-based SD formulation (Ma et al.2015).
Brucea javanica oil emulsion alleviates cachexia induced by Lewis lung cancer cells in mice
Published in Journal of Drug Targeting, 2018
Brucea javanica (L.) Merr, belongs to the family Simaroubaceae, and is an evergreen shrub widely distributed in Southeast Asia and northern Australia. Quassinoids that are extracted from the fruits (or seeds) of B. javanica, as the main active ingredients, possess various biological properties, such as anti-fungal, anti-oxidative, anti-inflammatory and anti-cancer properties [12–15]. Recent investigations have suggested that B. javanica could inhibit proliferation or induce apoptosis in human liver cancer, colon cancer, ovarian cancer, non-solid tumours such as leukaemia and so on. However, its effectiveness in cancer cachexia is still unknown [16–19].
Current medicines hold promise in the treatment of orphan infections due to brain-eating amoebae
Published in Expert Opinion on Orphan Drugs, 2021
Ruqaiyyah Siddiqui, Mohamed Yehia Abouleish, Mustafa Khamis, Taleb Ibrahim, Naveed Ahmed Khan
Among related protozoa, Entamoeba histolytica is a parasitic amoeba and a causative agent of amoebiasis that has remained a significant problem in human health. Intensive drug discovery research has identified a plethora of compounds to target E. histolytica[7]. Given the similarities in the cell biology, virulence traits such as proteases, motility, physiology, cellular differentiation, biochemistry etc., it is reasonable to test anti-E. histolytica compounds against pathogenic amoebae. Using the recently available genome information for brain-eating amoebae, it makes sense to investigate compounds with known parasite-specific target(s). As long as targets are confirmed in the brain-eating amoebae, this approach can be fruitful in identifying potentially novel bioactive molecules. Anti-protozoal compounds with demonstrated activity against E. histolytica are listed below and include synthetic as well as natural products[7]. Among synthetic thiosemicarbazones, two thiophene-2-carboxaldehyde thiosemicarbazones containing 4- benzylpiperidine and adamantamine moieties at N4 position are most active against amoebiasis. 2-Acetylpyridine dithiocarbazates, 1,2,4-triazine showed potent effects against E. histolytica. Among oxime ethers, µ-bis(oxo)bis{oxovanadium(V)} complexes of 2-acetylpyridine hydrazones derived from nicotinic acid & 2-furoic acid hydrazide displayed higher activity than metronidazole. Among bisphosphonates, bisphosphonates containing nitrogen were found bioactive against E. histolytica. Among alkaloids, emetine, isolated from Cephaelis ipecacuanha showed potent activity against Entamoeba. Naturally occurring alkaloid cryptopleurine, usambarensine, matrine, conessine, and benzylisoquinoline alkaloid, berberine exhibited activity. Among bisbenzylisoquinoline alkaloids, aromoline, isotrilobine, and insularine were found active against E. histolytica. Among quassinoids, triterpenes, quassin, glaucarubin showed bioactivity. Among nonalkaloid natural products, anemonin, mangostin, marmelosin, were anti-protozoal. Among iridoids, specioside, verminoside, and minecoside, showed anti-protozoal effects similar to metronidazole. Among flavonoids, luteolin, kaempferol, apigenin, showed potent effects. Among polyphenolic compounds, gossypol showed remarkably greater anti-protozoal effects when compared with metronidazole and worth investigation against pathogenic free-living amoebae.