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Molecular Biology Tools to Boost the Production of Natural Products
Published in Luzia Valentina Modolo, Mary Ann Foglio, Brazilian Medicinal Plants, 2019
Luzia Valentina Modolo, Samuel Chaves-Silva, Thamara Ferreira da Silva, Cristiane Jovelina da-Silva
The RNA interference (RNAi) or posttranscriptional gene silencing technology has become an important tool to speed up the breeding of medicinal plants, from which a conventional mutation breeding approach was shown to fail (Allen et al., 2004). The RNAi works by knocking down the expression of the target gene (Abbai et al., 2017). This provides an alternative to block the activity of enzymes that are encoded by a multigene family and are expressed in different plant tissues at distinct developmental stages. This technique has been employed to modulate the biosynthesis of morphine-like alkaloids (psychoactive drugs) by interfering with the activity of codeinone reductase (Allen et al., 2004). The gene that encodes for codeinone reductase was knocked down in Papaver somniferum plants (opium poppy) through DNA-directed RNAi, which resulted in the accumulation of (S)-reticuline, the precursor of isoquinoline alkaloid biosynthesis, at the expense of morphine, codeine, oripavine and thebaine (Allen et al., 2004). This same technique was used to block the activity of the berberine bridge enzyme in California poppy culture cells, also resulting in the accumulation of (S)-reticuline (Fujii et al., 2007). Recently, RNAi technology was used to elucidate the role of cytochrome CYP76AH1 in the metabolism of hairy roots of Salvia miltiorrhiza. The silencing of the CYP76AH1 gene affected the production of tanshinones (Ma et al., 2016). Therefore, this gene is a potential target for metabolic engineering in medicinal plants.
Catalog of Herbs
Published in James A. Duke, Handbook of Medicinal Herbs, 2018
Seed is reported to contain 4.3 to 5.2% moisture, 22.3 to 24.4% protein, 46.5 to 49.1% ether extract, 11.7 to 14.3% N-free extract, 4.8 to 5.8% crude fiber, 5.6 to 6.0% ash, 1.03 to 1.45% calcium, 0.79 to 0.89% phosphorous, 8.5 to 11.1 mg/100 g iron, 740 to 1181 μg/100 g thiamine, 765 to 1203 μg/100 g riboflavin, 800 to 1280 μg/100 g nicotinic acid; carotene is absent. Minor minerals in the seeds include 6 μg/kg iodine, 29 mg/kg manganese, 22.9 mg/kg copper, 15.6 g/kg magnesium, 0.3 g/kg sodium, 5.25 g/kg potassium, and 130 mg/kg zinc; the seeds also contain 2.80% lecithin, 1.62% oxalic acid, 3.0 to 3.6% pentosans, traces of narcotine, and an amorphous alkaloid; and the enzymes diastase, emulsin, lipase, and nuclease. Poppyseed oil cakes were estimated to have 88 feed units per 100 kg, 27.5% digestible crude protein, and 25.6% digestible true protein. Another analysis showed 54% organic matter, 87% crude protein, 100% crude fat, 0% crude fiber, and 48% N-free extract. The opium alkaloids are rather numerous, Duke97 having listed allocryptopine, apomor-phione, berberine, codeine, codeinone, corytuberine, cryptopine, desmethylepiporphyrox-ine, glaudine, gnoscopine, hydroxycodeine, isoboldine, isocorypalmine, lanthopine, laudanidine, laudanine, laudanosine, 6-methylcodeine, morphine, narcotine, narcotoiine, nornarceine, oxycryptopine, oxymorphine, oxynarcotine, palaudine, papaveraldine, papav-eramone, papaverine, papaverubines B, C, D, and E, protopine, pseudomorphine, reticuline, roemerine, salutaridine, salutaridinol-1, sanguinarine, and thebaine.
Metabolism of the areca alkaloids – toxic and psychoactive constituents of the areca (betel) nut
Published in Drug Metabolism Reviews, 2022
An unanticipated major in vivo metabolite of arecoline and arecaidine is N-methylnipecotic acid, a derivative lacking a double bond in the piperidinyl ring and containing a de novo chiral carbon with unknown stereochemistry. In regards to xenobiotic metabolism, this type of reduction is uncommon and it is not surprising that the enzyme(s) and tissue site(s) facilitating the reaction remain unknown. Giri et al. (2006), probably the first to identify this metabolite in vivo, postulated that N-methylnipecotic acid is formed from an acyl-CoA ester of arecaidine and a putative catalyst is trans-2-enoyl thioester reductase (Giri et al. 2006). Another possibility, in the author’s opinion, is the bacterial NADH-dependent morphinone reductase that reduces codeinone and morphinone to hydrocodone and hydromorphone, respectively (French and Bruce 1994). Morphinone reductase belongs to a class of oxidoreductases that are similar to the old yellow enzyme (OYE) family (Messiha et al. 2005). Messiha et al. (2005) showed that morphinone reductase metabolizes α/β unsaturated carbonyl compounds such cyclohexen-1-one (Messiha et al. 2005). The arecoline molecule, interestingly, contains an α/β unsaturated carbonyl system. Confirmation of enzymes driving stereospecific N-methylnipecotic acid formation is unknown, but possibly toxicologically relevant since removal of the double bond presumably abolishes the reactivity of arecoline with important cellular thiols. Thus, formation of N-methylnipecotic acid stereoisomers is a potential detoxification marker, clearly justifying further research.