China 
Africa 
Explore chapters and articles related to this topic
Bioengineering of Pharmacologically-Active Metabolites for Effective Drug Nano-Formulations from the Callus and Metabolites of Medicinal Plants and Their Significant Application in Nanomedicine
Published in Hajiya Mairo Inuwa, Ifeoma Maureen Ezeonu, Charles Oluwaseun Adetunji, Emmanuel Olufemi Ekundayo, Abubakar Gidado, Abdulrazak B. Ibrahim, Benjamin Ewa Ubi, Medical Biotechnology, Biopharmaceutics, Forensic Science and Bioinformatics, 2022
Charles Oluwaseun Adetunji, Akinola Samson Olayinka, Denisa Ficai, Anton Ficai, Michael Olugbenga Samuel, Wilson Nwankwo, Muhammad Akram, Rumaisa Ansari, Tehreen Riaz, Rida Zainab, Chukwuebuka Egbuna, Oluwaseyi Paul Olaniyan, Hameed Shah, Ruth Ebunoluwa Bodunrinde, Juliana Bunmi Adetunji, Jonathan C. Ifemeje, Michael Chinedu Olisah, Mohammad Ali Shariati, Kingsley Eghonghon Ukhurebor, Daniel Ingo Hefft, Wadzani Dauda Palnam
Terpenes (mono-, sesqui-, di- and triterpenes) are stored in glandular trichomes or oil cells as well as resin ducts and they are substances which are highly hydrophobic in nature. Terpenes building blocks are C5-units and they can be further sectioned into polyterpenes, (C10) monoterpenes, (C15) sesquiterpenes, (C20) diterpenes, (C30) triterpenes and (C40) tetraterpenes. (C27) Steroids are derivatives of triterpenes (Dewick 2001; Teuscher and Lindequist 2010). Biomembranes are usually interacted by most of them. An uncontrolled outward flow of ions and metabolites can ensue as a result of amplified fluidity of the membranes. Tempering of receptors and membrane proteins or even cell leakage causing cell death can also be a consequence of this. This membrane activity of terpenes being very non-specific affects several living organisms which may be microbes such as fungi, bacteria and some vertebrates, insects and even including the membrane-enclosed viruses. The toxicity of several diterpenes has also been reported. Protein kinase C is stimulated by phorbol esters leading to the production of severe inflammation. Andromedotoxin or Grayanotoxin I is frequent in Ericaceae and is reportedly strong blocker of sodium medium and therefore potent neuron toxicants (Wink and Van Wyk, 2008).
Biological Correlates of Microwave
Published in Jitendra Behari, Radio Frequency and Microwave Effects on Biological Tissues, 2019
The activation of this enzyme is thought to be biochemically dependent on Ca2+. Tumor promoting phorbol esters such as 12, O-tetradecanoyl phorbol-13-acetate (TPA) have a structure very similar to diacylglycerol and activate protein kinase C directly, both in vitro and in vivo (Castagna et al. 1982). It has been variously reported that protein kinase C is the receptor of tumor promoters (Parker et al. 1984). Tumor promoters such as phorbol esters increase the affinity of the enzyme for Ca2+, resulting in its full activation at physiological Ca2+ concentration. TPA has a specific membrane receptor in the cell membrane (Hunter et al. 1984). In order to stimulate cell proliferation in cells; growth factor and PKC are needed to induce the signal pathways. Byus et al. (1984) reported a decrease in the activity of this enzyme following exposure of human lymphocytes for a period of 15–30 min to 450 MHz amplitude modulated at 16 Hz. Paulraj and Behari (2004) also reported that the activity of this enzyme is affected due to RF exposure.
Modulated Fields and "Window" Effects
Published in Charles Polk, Elliot Postow, CRC Handbook of Biological Effects of Electromagnetic Fields, 2019
Elliot Poston, Mays L. Swicord
Reversible inhibition of allogenic cytotoxicity by murine T lymphocytes (CTLL-I) was reported89 in the presence of a 450-MHz field that was amplitude modulated at 60 Hz. Modulation frequencies between 3 and 40 Hz (including 16 Hz) as well as 80 and 100 Hz produced inhibitions of cytotoxicity that were not as large as the 20% inhibition observed at 60-Hz modulation. Unmodulated carrier waves did not influence cytotoxicity. Pretreatment with the RF field was also effective when it was modulated at 60 Hz. Both the requirement for calcium in the initial stage of the cytotoxic reaction and reports that HLF-modulated 450MH z fields affect calcium levels in brain tissue led the authors89 to suggest the involvement of calcium in the observed effect. More recently, Adey'x group extended their immunologic research to investigate the effect of amplitude-modulated RF fields (450 MHz) on protein kinase activity of human tonsil lymphocytes in culture.90 While the activity of cyclic-AMPdependent protein kinase was not affected by ELF-modulated fields, noncydic-AMP-dependent protein kinase was markedly decreased for a brief period of time (returning to control values in 45 min even though RF exposure continued). This effect is described as being "windowed" in both modulation frequency (16 to 60 Hz) and duration of exposure. These results are potentially important because of the role kinase may play in its interaction with cancer-promoting phorbol esters. However, more research must be completed before their meaning and import are put in proper perspective.
Targeting gap junctional intercellular communication by hepatocarcinogenic compounds
Published in Journal of Toxicology and Environmental Health, Part B, 2020
Kaat Leroy, Alanah Pieters, Andrés Tabernilla, Axelle Cooreman, Raf Van Campenhout, Bruno Cogliati, Mathieu Vinken
Phorbol esters are plant-derived tetracyclic diterpenoids, of which 4β-12-O-tetradecanoylphorbol-13-acetate has been well documented (Goel et al. 2007). The compound is derived from the croton plant and used commonly in research for tumor promoting and GJIC inhibiting activities (Goel et al. 2007; Roemer et al. 2013). Phorbol esters act as activators of PKC, which is responsible for signal transduction and developmental processes (Goel et al. 2007). Through direct action of PKC, 4β-12-O-tetradecanoylphorbol-13-acetate is able to dysregulate GJIC (Rivedal and Opsahl 2001; Sovadinova et al. 2015). This is, however, not the only pathway, as hyperphosphorylation of Cx43 on serine368 (Loch-Caruso et al. 2004) through MEK1/2, a mitogen-activated protein kinase, contributes to this inhibitory effect by producing internalization of Cx43 (Rivedal and Opsahl 2001; Sai et al. 1998; Sovadinova et al. 2015). ERK1/2 phosphorylation also inhibits GJIC (Jung et al. 2006). Further, Cx43 is internalized and degraded after ubiquitination mediated by both the PKC and the MAPK pathway (Leithe and Rivedal 2004; Rivedal and Leithe 2005).