China
Africa
Explore chapters and articles related to this topic
Bioactive Compounds in agricultural and Food production Waste
Published in Quan V. Vuong, Utilisation of Bioactive Compounds from Agricultural and Food Waste, 2017
Nenad Naumovski, Senaka Ranadheera, Jackson Thomas, Ekavi Georgousopoulou, Duane Mel lor
The three key triterpene groups include oleane, ursane and lupane triterpenes (Hill and Connolly 2011). The main triterpenoids found in the oleane category include oleanolic acid, erythrodiol and β-amyrin, whereas ursane and lupane families contain ursolic acid, uvaol; and lupeol, betulin and betulinic acid respectively (Han and Bakovic 2015). Oleanolic acid, maslinic acid, and β-amyrin are the chief compounds present in the oleanane triterpene family. These compounds are predominantly found in the skin of grapes, olives and tomatoes. Ursolic acid and uvaol are the chief compounds present in the ursane family. They are mainly present in the cuticle of apples (Han and Bakovic 2015). The chief compounds of lupine family, namely lupeol, betulin and betulinic acid are mainly found in the cuticle of mangoes and grape berries. Triterpenoids, in their free and esterified form are found to have low polarity. Therefore they are found in abundance in plant parts, such as surface cuticle waxes and stem bark (Szakiel et al. 2012). Therefore, fruit peels serve as a promising and highly available source material for such bioactive components (Jager et al. 2009).
Synthesis And Transformations Of 2,3-Secotriterpene Derivatives Of Betulin
Published in Alexander V. Kutchin, Lyudmila N. Shishkina, Larissa I. Weisfeld, Gennady E. Zaikov, Ilya N. Kurochkin, Alexander N. Goloshchapov, Chemistry and Technology of Plant Substances, 2017
Irina A. Tolmacheva, Natalia V. Galaiko, Ekaterina V. Igosheva, Anastasiya V. Konysheva, Alexey V. Nazarov, Gulnaz F. Krainova, Marina N. Gorbunova, Eugene I. Boreko, Vladimir F. Eremin, Victoria V. Grishko
Many examples of the chemical transformation of triterpenoids give more active semisynthetic derivatives which indicate the promise for derivatives obtained by introducing a heterocyclic fragment condensed with ring A of the triterpene skeleton [52]. Lupane and 18aH-oleanane a-hydroximino ketones (5), (6), cyclic precursors of semisynthetic 2,3-pentacyclic triterpenoids, provide a platform for the annelation of triterpene skeleton with heterocyclic rings. Heating a-hydroximino ketones (5), (6) in refluxing pyridine with excess acetyl chloride leads to formation of three reaction products: A-acetyl-substituted enamines (160), (161), C(1)-C(2)- fused isoxazoles (162), (163), and C(2)-C(3)-fused oxazoles (164), (165) which the chemical yields 15-18%, 31-36%, and 24-26%, respectively [21] (Fig. 1.19). Cyclization of A-acetylhydrazones obtained in situ from a-hydroximino ketones (5), (6) gave C(2)-C(3)-fused 2’-A-ace’tyl-1,2,3-triazoles (166), (167) which was hydrolyzed in unsubstituted 1,2,3-triazoles (168), (169). The acylation of 18aH-oleanane 1,2,3-triazole (169) by acetyl chloride in pyridine leads to formation of a mixture of T-A- and 3’-A-acetyl derivatives (171) and (172) with virtually identical yields (48% and 47%, respectively). We should note that using hydrazine hydrate instead of acetylhydrazide in the preparation of the 1,2,3-triazoles from a-hydroximino ketones (5), (6) enhances the yields of 2’-A-acetyl-1,2,3-triazoles (166), (167) to 60%. Up to 10%, T-A-acetyl-1,2,3-triazoles, (169) (171) were formed in this reaction [21] (see Fig. 1.19).
Lipid biomarkers as organic matter source indicators of estuarine mangrove ecosystems
Published in Chemistry and Ecology, 2022
C. S. Ratheesh Kumar, O. S. Gayathry, V. B. Rakesh, A. Sudha, Roshni Mohan, P. M. Salas, P. Resmi, Manju Mary Joseph, K. Shameem, N. Chandramohanakumar
Oleanane class of terpenoids found in petroleum and aged sediments, formed by diagenetic alteration of the respective compounds with angiosperm source indication [75,76]. These peculiar types of organic compounds are predominantly enriched in mangrove leaves and Seagrass blades [50,56]. Olean-12-ene and urs-12-ene are mainly alteration products of β- and α-amyrin, respectively [77]. The fundamental ring structure of oleanene and oleanoid class of terpenoids generate from a common biochemical mechanism in higher plants, therefore the occurrence of these compounds suggested the formation of oleanane-type compounds during diagenesis. Moreover, the occurrence of 3-oxygenated pentacyclic triterpenes in surface sediments strongly implied that microbiological processes were responsible for their formation [68,71] and is generally considered as molecular markers for evaluating terrigenous vascular plant input. Olean-12-ene (3-oxygenated pentacyclic triterpene), detected in all the samples (Figure 3(e)), could be regarded not only as a molecular marker of terrestrial higher plants but also provides an indication of diagenetic transformations occurring in the sedimentary environment [75,76]. Taraxer-14-ene detected in sediments of M3 (Table 2) might be attributed to mangrove origin [75] and its absence in other sites could be due to its rapid transformation to diagenetic intermediates, i.e. isomerisation of taraxer-14-ene to olean-12-ene [78]. On the other hand, the occurrence of lup-20(29)-en-3-one at M2, a component of bark and leaves of higher plants including mangroves indicated mangrove input [54]. β-amyrenone and α-amyrenone are common constituents of higher plants, usually found in epicuticular waxes and in the tree bark of angiosperms can also originate by oxidation of the corresponding β-amyrin and α-amyrin [24,68,69]. Derivatives of β-amyrin exhibit dominance over derivatives of α-amyrin since the former could be degraded more preferentially than the latter [68] and the investigation recorded β-amyrenone in all the mangrove systems and E1 of the estuary.