Chemopreventive Agents
David E. Thurston, Ilona Pysz in Chemistry and Pharmacology of Anticancer Drugs, 2021
Diterpenes (also called diterpenoids) are a highly diverse C20-subclass of terpenoids comprised of four isoprene units. Diterpenes are biosynthesized by animals, plants, and fungi, and form the basis for biologically essential compounds including retinal, retinol, and phytol, as well as compounds with reported chemopreventive activity such as cafestol and kahweol (Figure 12.29), which are described below. Structures of the diterpenoids cafestol and kahweol.
Anti-Cancer Agents from Natural Sources
Rohit Dutt, Anil K. Sharma, Raj K. Keservani, Vandana Garg in Promising Drug Molecules of Natural Origin, 2020
Diterpenoids consist of four isoprene subunits and contain a C20 skeleton in general. Diterpenoids are can be found plentiful in many terrestrial plants, fungi, and few animals. Euphorbia fischeriana Steud, a spurge family known to contain many anticancer diterpenoids (Barrero et al., 2011). In E. fischeriana, diterpenoid subtype ent-abietane is found. Jolkinolide B, a member of the ent-abietane subtype, could trigger apoptosis in hepatic, breast, gastric, and cervical tumor cells (Wang et al., 2013). Jolkinolide B inhibited the JAK2/STAT3 pathway in HL-60 and THP-1 cells by downregulation of JAK2/STAT3 and bcl-2, two important regulating proteins. Furthermore, jolkinolide B caused an upregulation of Bax and cytosolic cytochrome c, which triggered certain caspase to instigate apoptosis in leukemic cells (Lin et al., 2012; Wang et al., 2011). Jolkinolide B also inhibited metastasis in human breast cancer MDA-MB-23 cell lines through the detachment of fibronectin. Fibronectin is a glycoprotein having ability to alter cell growth, migration, and metastasis; it can also bind to integrins. Inhibition of fibronectin can greatly reduce cell migration and related metastasis (Pankov et al., 2002). Future research is being conducted on diterpenoid’s ability to detach fibronectin from cancerous cells. Many other anticancer diterpenoids, e.g., prostratin and 17-Acetoxyjolkinolide B have demonstrated antineoplastic ability. Prostratin has the potential to reduce cellular proliferation selectively in breast tumors. While 17-acetoxyjolkinolide B inhibits NF-κB and subsequently promotes apoptosis (Figure 5.24).
Essential Oils and Volatiles in Bryophytes
K. Hüsnü Can Başer, Gerhard Buchbauer in Handbook of Essential Oils, 2020
These spore-forming plants are also rich sources of a number of different skeletal diterpenoids. In the essential oils obtained from liverwort species, diterpene hydrocarbons and simple alcohols can be found. Volatile extracts are more rich in the diterpenic compounds. The most prevalent are clerodane, kaurane, and labdane skeletons. Compounds of spiroclerodane, 5,10-seco-clerodane (e.g., 26), 9,10-seco-clerodane, epi-homoverrucosane, seco-infuscane, infuscane, abeo-labdane (e.g., 27), and sacculatane (e.g., 28, 29) types are representatives of diterpenoids found only in the liverworts.
Screening of in vitro antimicrobial activity of plants used in traditional Indonesian medicine
Published in Pharmaceutical Biology, 2018
Andreas Romulo, Ervizal A. M. Zuhud, Johana Rondevaldova, Ladislav Kokoska
In this study, leaf extract of O. aristatus exhibited inhibitory activity against C. albicans, E. faecalis, S. aureus and P. aeruginosa. This is in correspondence with previously published results showing the antimicrobial effect of methanol and ethanol leaf extract of O. aristatus against S. aureus, P. aeruginosa (Ho et al. 2010; Vijayan et al. 2013) and C. albicans (Neharkar and Laware 2013), as determined by disk and agar diffusion methods. In addition, the essential oil of O. aristatus leaf has also been reported as exhibiting antifungal properties against several plant pathogens such as Botrytis cinerea, Colletotricum capsici, Fusarium solani, Phytophthora capsici and Rhizoctonia solani (Hossain et al. 2008). Di et al. (2013) isolated several new diterpenoid compounds (orthoarisins) from an ethanol aerial extract of O. aristatus. Many reports have extensively shown that diterpenoids exert significant antimicrobial effects (Veneziani et al. 2017). Olah et al. (2003) reported the presence of polymethoxylated flavonoids and caffeic acid derivatives, mainly rosmarinic acid in an ethanol leaf extract of O. aristatus. This compound has been known to possess antimicrobial activity against a broad spectrum of bacteria and yeasts (Gohari et al. 2010; Salawu et al. 2011). It can be assumed that these compounds may contribute to the broad-spectrum antimicrobial potential of O. aristatus found in the present study.
Biogenic synthesis and characterization of silver nanoparticles using aqueous leaf extract of Scoparia dulcis L. and assessment of their antimicrobial property
Published in Drug and Chemical Toxicology, 2020
In summary, plant aqueous extract could be used as an efficient green material for rapid and reliable synthesis of nanoparticles. In the present study, silver nanoparticles were synthesized using S. dulcis aqueous leaf extract. By changing the quantity of plant extract, silver ion concentration, and reaction time at room temperature, the size of nanoparticles was varied. Aqueous plant mediated the structured patterning of nanoparticles into spheres. At optimum conditions, FCC structure with diameter range of 3 to 18 nm have been envisaged without chemical reagent and was stable for more than 3 months. Color change occurs due to Surface plasmon resonance during the reaction with the phytochemicals present in the leaf extract. The development of nanoparticles was monitored by UV-Vis spectroscopy and the particle size was measured by DLS. Characterization of silver nanoparticles was evaluated by TEM and XRD analysis at optimum conditions. FTIR analysis confirmed the bioreduction of Ag+ ions to AgNPs by various functional groups. Moreover, the synthesized nanoparticles exhibit a pronounced antibacterial activity against different tested microorganisms. It is already known that the isolated different types of biologically active diterpenoids from the aerial parts of S. dulcis showed cytotoxicity against different cancer cell lines. These AgNPs could be a potential candidates to target the cancer cells. In this study, the synthesized AgNPs using S. dulcis aqueous leaf extract, in nanoformulation could be a better approach to enhance the efficacy of plant extracts.
Frankincense diterpenes as a bio-source for drug discovery
Published in Expert Opinion on Drug Discovery, 2022
Hidayat Hussain, Luay Rashan, Uzma Hassan, Muzaffar Abbas, Faruck L. Hakkim, Ivan R. Green
The verticillane-type diterpene named (1S,3E,7E,11 R)-verticilla-3,7,12(18)-triene (77) was reported from B. serrata and demonstrated antimalarial effects against Plasmodium falciparum with IC50: 9.2 µM and a selectivity index of 8.8. On the other hand, this compound was not effective in a cytotoxic investigation toward L6 rat skeletal myoblasts [82]. Prenylaromadendrane-type diterpenoids 78 and 79 along with boscartols B (69), C (70) and F (72) were isolated from B. sacra. Interestingly, all these diterpenoids displayed significant cytotoxic effects toward the U87-MG (malignant glioma) cell line with inhibitory rates ranging from 33.9 to 55.3 %. Notably, the activities of these molecules were higher than the standard 5-fluorouracil (30.4%) [88].
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