Anti-inflammatory Diterpenoids from Croton tonkinensis

Abstract

Phytochemical investigation of the methanolic extract of Croton tonkinensis afforded two known kauranes (1, 2), eight new ent-kauranes (3-10), and 16 known ent-kaurane-type diterpenoids (12-27). In addition, 30 known compounds were identified by comparison of their physical and spectroscopic data with reported data. Among the isolated compounds, ent-18-acetoxykaur-16-en-15-one (20) displayed the most significant inhibition of superoxide anion generation and elastase release.

The Constituents of the Stems of Cissus assamica and Their Bioactivities

“…The crude extract was suspended in water and then partitioned with chloroform and n -butanol successively to afford chloroform, n -butanol, and water layers, respectively. Purification of the three layers by column chromatography yielded a mixture of β-sitosterol ( 1 ) and stigmasterol ( 2 ) [27], β-sitosteryl glucoside ( 3 ) [28], a mixture of 3β-hydroxyl stigmast-5-en-7-one ( 4 ) and 3β-hydroxystigmast-5, 22-dien-7-one ( 5 ) [29], a mixture of β-sitostenone ( 6 ) [30] and stigmasta-4,22-dien-3-one ( 7 ) [31], 6β-hydroxy-β-sitostenone ( 8 ) [32], ergosterol peroxide ( 9 ) [33], 3,5,7,4′-tetramethoxyflavone ( 10 ) [34], 3′,4′,3,6,7-pentamethoxyflavone ( 11 ) [35], 3′,4′,5,6,7-pentamethoxyflavone ( 12 ) [35], 4′,5,6,7-tetramethoxy-flavone ( 13 ) [36], a mixture of oleanolic acid ( 14 ) [30] and ursolic acid ( 15 ) [28], betulinic acid ( 16 ) [37], friedelin ( 17 ) [38], epi -glut-5(6)-en-ol ( 18 ) [39], taraxerol ( 19 ) [9], epi -friedelinol ( 20 ) [40], glutinone ( 21 ) [41], lup-28-al-20(29)-en-3-ol ( 22 ) [42], a mixture of α-amyrin ( 23 ) and β-amyrin ( 24 ) [43], bergenin ( 25 ) [44], p -hydroxybenzaldehyde ( 26 ) [45], vanillin ( 27 ) [30], methyl gallate ( 28 ) [46], gallic acid ( 29 ) [47], 4-methoxybenzoic acid ( 30 ) [48], vanillic acid ( 31 ) [30], a mixture of 4-hydroxy- trans -cinnamic acid methyl ester ( 32 ) and 4-hydroxy- cis -cinnamic acid methyl ester ( 33 ) [49], a mixture of octadecyl- trans -ferulate ( 34 ) and octadecyl- cis -ferulate ( 35 ) [50], 1-(4-methoxy-phenyl)undecan-1-one ( 36 ) [51], 3-hydroxy-4-methoxybenzoic acid ( 37 ) [52], hexadecyl ferulate ( 38 ) [45], 2-hydroxybenzoquinone ( 39 ) [53], 2,6-dimethyoxybenzoquinone ( 40 ) [49], 3,3′,4-tri- O -methyl-ellagic acid ( 41 ) [54], 3,3′,4,4′-tetra- O -methylellagic acid ( 42 ) [55], methyl pheophorbide-a ( 43 ) [49], a mixture of methyl-21-hydroxy-(21 S )-pheophorbide-a ( 44 ) and methyl-21-hydroxy-(21 R )-pheophorbide-a ( 45 ) […”

In vitro antituberculosis activity of diterpenoids from the Vietnamese medicinal plant Croton tonkinensis

“…However, the Croton diterpenoids from CT extract typically contained kaurane-, ent-kaurane-and grayanane-type skeletons [11][12][13][14][15]20]. Figure 1 shows the structures of the diterpenoids from CT extract.…”

“…Although other solvent fractions (ethanol, nhexane, ethyl acetate fractions) also showed anti-TB activity, it was postulated that this antimycobacterial activity might be due to the presence of different diterpenoids in the CT extracts. The reasoning for this postulation was drawn from the previous studies as diterpenoids were found to be the main constituents of CT extracts (11)(12)(13)(14)(15)(20)(21)(22). Tuberculosis (TB) poses a global threat to mankind because of the rapid emergence of MDR-and XDR-TB strains, which are usually uncontrollable with the available treatment regimen.…”

“…Vu Van Chuyen at Hanoi College of Pharmacy (Hanoi, Vietnam). The methodology for extraction of the compounds can be found elsewhere [11][12][13][14][15][20][21][22]. Furthermore, an activity-guided bioassay was done in fractionated croton extracts (ethanol, n-hexane, methylene chloride, ethyl acetate) to confirm the initial antimycobacterial activity of the extracts by microtiter resazurin as described below.…”

“…A plant extract of Croton tonkinensis has been reported to contain steroids, alkaloids and terpenoids as its main constituents, being especially rich in diterpenoids [11][12][13]. Croton compounds from C. tonkinensis containing diterpenoids were shown to have various bioactivities in vitro, including antiinflammatory, antitumor, osteogenesis and antioxidative activity [14,15].…”