Other plant compounds

A variety of other plant compounds are bioactive as toxins, pro-toxins, sweet or bitter tas-tants, odorants, semiochemicals, enzyme inhibitors, receptor agonists, receptor antagonists or psychoactive agents. The structure and bioactivity of non-alkaloid, non-phenolic and non-terpenoid plant compounds is briefly reviewed below. Some selected structures of cyclic compounds in this category are shown in the Appendix (Section 4). 

Sugars are further classified by the number of carbons. Thus, aldoses include aldotrioses (C3 D-glyceraldehyde, HO—CH2—GHO), aldotetroses (Gy D-erythrose) aldopentoses (C-, D-ribose, D-arabinose, D-xylose) and aldohexoses (Ce D-glucose, D-mannose, D-gulose, D-galactose). Ketoses include ketotrioses (Gy dihydroxyacetonephosphate, HO-CH2-CO— CH2OH), ketotetroses (C D-erythrulose), ketopentoses (C3 D-ribulose, D-xylulose) and ketohexoses (C6 D-fructose). 

Carboxylic acids. Aliphatic carboxylic acids (R—GOOH) are deprotonated at physiological pH (pH 7) and are therefore represented as R—COO. Thus, acetic acid (GHj—COOH) exists as acetate (CH3COO ) at pH 7. A variety of short chain mono-, di-and tricarboxylic acids are important intermediates in metabolism and may be present at low concentrations in all cells either as the acid or as a covalent adduct. Thus, acetate (C2) and malonate (C3) can exist as the key acyl-coenzyme A thioester intermediates acetylGoA and malonylCoA, respectively. Phosphoenolpyruvate (C3), 1,3-bisphosphoglyceric acid (C3) and 3-phosphoglyc,erate (C3) are key metabolic intermediates. 

The arylacetylene phenylheptatriyne (Phe—C=C—C=C—C=C—CH 3) from Bidens, Dahlia and Coreopsis species (Asteraceae) has phototoxic antimicrobial activity as have 5-(3-buten-l-ynyl)-2,2 -bithienyl (thiophene—thiophene—C=C—C=CH2) and the cyclic disulfide acetylenes thiarubrine A (C3—(C4,S—S)—C6) and thiarubrine B (Cj-(C4,S-S)-C3). The photoactivation of acetylenes derives from light absorption by these conjugated systems and ready reaction with oxygen to form reactive intermediates. 

Alkyl sulfides and thiols. Some alkyl thiols and sulfides, notably those from commonly ingested Allium sativum (garlic) and Allium cepa (onion) (Alliaceae), are variously bioactive as odorants and antimicrobials. Propanethial S-oxide (CH3-CH2-CH=S=0) is a lachrymatory irritant principle of onion. Allicin (S-oxodiallydisulfide CH2=CH—CH2-SO-S-CH2— CH=CH2), diallyldisulfide (CH2=CH-CH2-S-S-CH2-CH=CH2) and diallylsulfide (CH2=CH—CH2—S—CH2-CH=CH2) are major odorants of garlic that are reactive and irritant because of the allyl groups. Dimethyl disulfide (CH3—S—S-CH3), dipropyl disulfide (CH3-CH2-CH2-S-S-CH2-CH2-CH3), methyl allyl disulfide (CH3-S-S-CH2-CH=CH2) and propane-1-thiol (CH3-CH2—CH2—SH) are further Allium odorants. Methane thiol (methyl mercaptan CH3—SH) is a widespread plant volatile and notably derives from anaerobic bacterial degradation of cysteine as in human flatus and bad mouth odour. The aliphatic disulfides allicin and ajoene inhibit proinflammatory expression of iNOS. 

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In summary, natural plant compounds have been exploited commercially as sources (e.g., pyrethrins, rotenoids, alkaloids) and models (e.g., pyrethrins, physostlgmine) of insecticides. Other plant compounds are currently being evaluated for similar uses (e.g., chromenes, limonoids). Still others are being evaluated for use in host plant resistance (e.g., long-chain methyl ketones). Such novel chemicals with potent and often unique biological activities will continue to be discovered and exploited through bioassay and... 

Coupling of such radicals yields a great variety of products. One type of dimerization gives the stable ether linked pinoresorcinol (Eq. 25-11). Through a complex sequence of reactions, it can be converted into other plant compounds including the phytoalexin plicatic acid, a major component of western... 

Ligninases Removal of burrs and other plant compounds from raw wool... 

The ease with which amines are extracted into aqueous acid combined with their regeneration on treatment with base makes it a simple matter to separate amines from other plant materials and ni trogen containing natural products were among the earliest organic compounds to be studied Their basic... 

Other auxin-like herbicides (2,48) include the chlorobenzoic acids, eg, dicamba and chloramben, and miscellaneous compounds such as picloram, a substituted picolinic acid, and naptalam (see Table 1). Naptalam is not halogenated and is reported to function as an antiauxin, competitively blocking lAA action (199). TIBA is an antiauxin used in receptor site and other plant growth studies at the molecular level (201). Diclofop-methyl and diclofop are also potent, rapid inhibitors of auxin-stimulated response in monocots (93,94). Diclofop is reported to act as a proton ionophore, dissipating cell membrane potential and perturbing membrane functions. 

A large use of molecular sieves ia the natural gas industry is LPG sweetening, in which H2S and other sulfur compounds are removed. Sweetening and dehydration are combined in one unit and the problem associated with the disposal of caustic wastes from Hquid treating systems is eliminated. The regeneration medium is typically natural gas. Commercial plants are processing from as Htde as ca 30 m /d (200 bbl/d) to over 8000 m /d (50,000 bbl/d). 

Some nut trees accumulate mineral elements. Hickory nut is notable as an accumulator of aluminum compounds (30) the ash of its leaves contains up to 37.5% of AI2O2, compared with only 0.032% of aluminum oxide in the ash of the Fnglish walnut s autumn leaves. As an accumulator of rare-earth elements, hickory greatly exceeds all other plants their leaves show up to 2296 ppm of rare earths (scandium, yttrium, lanthanum, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium). The amounts of rare-earth elements found in parts of the hickory nut are kernels, at 5 ppm shells, at 7 ppm and shucks, at 17 ppm. The kernel of the Bra2d nut contains large amounts of barium in an insoluble form when the nut is eaten, barium dissolves in the hydrochloric acid of the stomach. 

There are two main processes for conversion of celestite, ie, strontium sulfate, to strontium carbonate. The principal process is the black ash process. Strontium nitrate is produced by dissolving celestite in nitric acid and purifying it. Most other strontium compounds are produced from strontium nitrate. To service this market, NOAH Technologies Corporation (San Antonio, Texas) has estabUshed a plant in Mexico to manufacture most commercial- and reagent-grade strontium compounds except strontium carbonate. 

Photoautotrophs CO2 Light H2O, H2S, S, other inorganic compounds Green plants, algae, cyanobacteria, photosynthetic bacteria... 

Hydrocyanic acid, HCN, also known as prussic acid, or formo-nitrile, is the product of decomposition of numerous glucosides found in a very large number of plants, usually together with some other volatile compound, so that essential oils containing hydrocyanic acid do not, for practical purposes, exist in the first instance as such in the plant, but are only developed on the decomposition of the glucoside. 

The toxic influence exerted by Juglans nigra (black walnut) on other plants has been attributed to 5-hydroxy-1,4-naphthoquinone (juglone) (11,31). Hydrojuglone is present in the root bark, leaves, and fruit husks. This compound is not considered toxic, but it is oxidized to the toxic juglone upon exposure to air (51). Rainfall... 

The first soaps were probably the saps of plants such as Chloro-galum pomeridianum, the roots of which can be crushed in water to form a lather. Other plants, such as soapbark (Quillaja saponaria), soapberry (Sapindus mukorossi), and soapwort (Saponaria officinalis) also contain the same main ingredient, a compound called saponin, which forms the foamy lather. 

Proof-of-concept through new pharmaceuticals. We have generated preliminary data suggesting that one of Rumphius s purported pharmaceuticals does have the medicinal properties described. However, it has not been shown that the active compound is novel. Examining other plants identified in historic herbal texts for their purported medicinal properties may ultimately show that novel pharmaceuticals can be developed by mining historic herbal texts. 

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