Esters and other constituents of the foliar cuticular wax of a soybean variety

The constituents of the foliar cuticular wax of the variety ‘MG/BR 46 Conquista’ were isolated and chemically characterized. N-Alkanes, esters and triterpenoids are major constituents of the cuticular wax. Esters, taraxerol and steroids seem to be valuable cuticular wax constituents for characterization and distinction among soybean varieties.     

Cloning and Characterization of Oxidosqualene Cyclases from Kalanchoe daigremontiana: ENZYMES CATALYZING UP TO 10 REARRANGEMENT STEPS YIELDING FRIEDELIN AND OTHER TRITERPENOIDS*

The first committed step in triterpenoid biosynthesis is the cyclization of oxidosqualene to polycyclic alcohols or ketones C₃₀H₅₀O. It is catalyzed by single oxidosqualene cyclase (OSC) enzymes that can carry out varying numbers of carbocation rearrangements and, thus, generate triterpenoids with diverse carbon skeletons. OSCs from diverse plant species have been cloned and characterized, the large majority of them catalyzing relatively few rearrangement steps. It was recently predicted that special OSCs must exist that can form friedelin, the pentacyclic triterpenoid whose formation involves the maximum possible number of rearrangement steps. The goal of the present study, therefore, was to clone a friedelin synthase from Kalanchoe daigremontiana, a plant species known to accumulate this triterpenoid in its leaf surface waxes. Five OSC cDNAs were isolated, encoding proteins with 761–779 amino acids and sharing between 57.4 and 94.3% nucleotide sequence identity. Heterologous expression in yeast and GC-MS analyses showed that one of the OSCs generated the steroid cycloartenol together with minor side products, whereas the other four enzymes produced mixtures of pentacyclic triterpenoids dominated by lupeol (93%), taraxerol (60%), glutinol (66%), and friedelin (71%), respectively. The cycloartenol synthase was found expressed in all leaf tissues, whereas the lupeol, taraxerol, glutinol, and friedelin synthases were expressed only in the epidermis layers lining the upper and lower surfaces of the leaf blade. It is concluded that the function of these enzymes is to form respective triterpenoid aglycones destined to coat the leaf exterior, probably as defense compounds against pathogens or herbivores.     

Chemical constituents isolated from Clematis akebioides (Maximowicz) Veitch

A phytochemical investigation of the aerial parts of Clematis akebioides (Maximowicz) Veitch led to the isolation of eighteen compounds, including two benzenoids (1, 2), one linear monoterpene glycoside (3), and fifteen triterpenoid saponins (4–18). The structural elucidation of these compounds was determined by using spectroscopic methods and comparison with the literature. All of these compounds were obtained from C. akebioides for the first time, and compounds 1, 2 and 18 were isolated from the Ranunculaceae family for the first time. Furthermore, the chemotaxonomic significance of these compounds was discussed.     

Dual-stage triterpenoids from an African medicinal plant targeting the malaria parasite

Sixteen triterpenoids (1–16), previously isolated from the aerial parts of the African medicinal plant Momordica balsamina or obtained by derivatization, were evaluated for their activity against liver stages of Plasmodium berghei, measuring the luminescence intensity in Huh-7 cells infected with a firefly luciferase-expressing P. berghei line, PbGFP-Luc_con. Toxicity of compounds (1–16) was assessed on the same cell line through the fluorescence measurement of cell confluency. The highest activity was displayed by a derivative bearing two acetyl residues, karavoate B (7), which led to a dose-dependent decrease in the P. berghei infection rate, exhibiting a very significant activity at the lowest concentration employed (1 μM) and no toxicity towards the Huh-7 cells. It is noteworthy that, in previous studies, this compound was found to be a strong inhibitor of blood-stages of Plasmodium falciparum, thus displaying a dual-stage antimalarial activity.     

樟芝产生三萜类化合物的液体培养条件的响应面法优化

樟芝(Antrodia cinnamomea)是一种非褶菌目、多孔菌科的多年生蕈菌类,樟芝子实体中含有多种生理活性物质包括三萜类化合物,但野生樟芝只生长在台湾特有的牛樟树树干腐朽的心材内壁和枯死倒伏的牛樟树表面,生长极其缓慢,很难获得,价格昂贵。本研究的目的是通过液体培养樟芝的菌丝体以产生三萜类化合物,用响应面法优化了樟芝产生三萜类化合物的液体发酵条件。首先对樟芝的液体发酵的培养基成分及培养条件进行了单因素优化,研究发现樟芝液体发酵产生三萜类化合物的最佳碳源和氮源分别为葡萄糖和酵母提取物,最佳浓度分别为100 g/L和9 g/L,优化的培养基配方为(g/L):葡萄糖100.0,酵母提取物9.0,Mg SO4·7H2O 0.5,KH2PO41.0。优化的培养条件为:初始pH值6.0,温度28℃,接种量10%(v/v),摇床转速180 r/min。在此基础上,用响应面法对樟芝液体发酵产生三萜类化合物影响最大的三个因素即碳源、氮源和培养温度进行了优化,结果优化的三种因素条件为:葡萄糖104.71 g/L,酵母提取物9.93 g/L,温度28.42℃。用优化的培养条件液体培养樟芝,其三萜类化合物的产量达到391.45 mg/L,比优化前的产量223.39 mg/L提高了75.23%,为进一步研究液体培养樟芝产生三萜类化合物奠定了基础。     

蛇菰的化学成分

从蛇菰科植物蛇菰 (BalanophoraharlandiiHook .f.)花序的乙醇提取物中分离到 11个化合物。分别鉴定为 :桐甾醇 (1)、桐甾醇 - 3-O - (6′ -O -棕榈酰基 ) - β -D -葡萄吡喃糖甙 (2 )、 (- ) -lariciresinol (3)、 (- ) -松脂醇 [(- ) -pinoresinol](4 )、β -香树脂醇 (5)、乙酸蛇麻脂醇酯 (6 )、棕榈酸 (7)、 1-O -咖啡酰基 - β -D -葡萄吡喃糖 (8)、 1-O -咖啡酰基 - (6 -O -没食子酰基 ) - β -D -葡萄吡喃糖 (9)、 1-O -咖啡酰基 - (4 -O-没食子酰基 ) - β -D -葡萄吡喃糖 (10 )以及没食子酸 (11)。应用 2DNMR技术对化合物3,4 ,8,9和 10的氢和碳的核磁共振信号进行了全归属。化合物 9和 10尚未见从植物中分离到的报道 ,化合物 1,2 ,8和 11系首次从该科植物中分离得到。     

Simultaneous production of anthocyanin and triterpenoids in suspension cultures of Perilla frutescens

When cultivated in Murashige & Skoog medium supplemented with 0.2 mg l⁻¹ 2,4-dichlorophenoxy acetic acid and 0.5 mg l⁻¹ 6-benzyladenine, Perilla frutescens cells in suspension culture grew rapidly reaching about 13.6 g dry wt l⁻¹ after 12 days. The cell line produced both anthocyanin 0.9 g l⁻¹ and triterpenoids: 16 mg l⁻¹ oleanolic acid (OA), 25 mg l⁻¹ ursolic acid (UA) and 14 mg l⁻¹ tormentic acid (TA). When P. frutescens cells of 7-day-old cultures were exposed to a yeast elicitor at 0.5–5% (v/v) for 7 days, it was found that anthocyanin content peaked at 10.2% of dry weight with yeast elicitor at 1% (v/v) whereas the maximum production of oleanolic acid and ursolic acid in cultures treated with 2% (v/v) yeast elicitor was 19 and 27 mg l⁻¹, a 46 and 24% increase over the control, respectively. This is the first report of simultaneous production of both anthocyanin and triterpenoids in a single culture system.     

Cytotoxic Triterpenoids from the Barks of Betula platyphylla var. japonica

Phytochemical investigation on the barks of Betula platyphylla var. japonica (Betulaceae) was carried out, resulting in the isolation and identification of three new triterpenoids, 27‐O‐cis‐caffeoylcylicodiscic acid ( 1 ), 27‐O‐cis‐feruloylcylicodiscic acid ( 2 ), and 27‐O‐cis‐caffeoylmyricerol ( 3 ), along with six known triterpenoids, obtusilinin ( 4 ), winchic acid ( 5 ), 27‐O‐trans‐caffeoylcylicodiscic acid ( 6 ), uncarinic acid E ( 7 ), myriceric acid B ( 8 ), and 3‐O‐trans‐caffeoyloleanolic acid ( 9 ). The structures of the new compounds were elucidated by extensive spectroscopic methods, including 1D‐ and 2D‐NMR, and HR‐ESI‐MS. All of the isolated compounds were evaluated for cytotoxicity against four human tumor cell lines (A549, SK‐OV‐3, SK‐MEL‐2, and Bt549). Compounds 2 , 6 , 8 , and 9 exhibited potent cytotoxicity against all of the tumor cells tested (IC₅₀ < 10.0 μm ), while compounds 3 , 4 , 5 , and 7 showed moderate cytotoxicity against all of the tumor cells tested (IC₅₀ < 20.0 μm ).