Microbial transformation of sclareol.

Abstract

The microbial transformation of sclareol, a tobacco constituent, by a soil bacterium JTS-162 was studied. Manool, manoyl oxide and a new compound; 14,15-dinorlabd-8(17)-en-13-one were isolated from the culture broth as transformation products. In the presence of metabolic inhibitors such as a,a'-dipyridyl, a compound; labda-8(17),14-dien-1 3/?,18-diol and two new compounds; 13/5hydroxylabda-8(17), 14-dien-18-al and 13/?-hydroxylabda-8(17),14-dien-18-oic acid were accumulated in the culture broth as transformation products. Based on the experiments with degradation sequence, the biotransformation pathway of sclareol by the bacterium was proposed. The microbial transformation of diterpenoids has not been studied so muchas that of monoterpenoids. Only the microbial conversion of abietic acid and its related compounds was studied in detail.1>2) In the previous paper,3) we reported the microbial transformation of cw-abienol [(12Z)-labda-12,14-diene], a major labdane of tobacco leaf wax. This was attempted to obtain new aroma compounds for tobacco flavoring by an unidentified soil bacterium, JTS-162. This microorganism first dehydrated cw-abienol at C-8 and C-17 positions and produced (12Z)-labda-8(1 7), 12,14-triene. This triene was oxidized stepwise at its a-methyl group at C-4 to give (12Z)-labda-8(17),12,14trien-18-ol and (12Z)-labda-8(17),12,14-trien-18-al. Next step of conversion was splitting of A-ring and resulted in 4, 18, 19-trinor-3,4-,s<m?-5-oxo-(12Z)-labda-8(17), 12, 14-trien-3-oic acid in the culture broth. On the other hand, sclareol [labd-14-en-13/?ol] has also been isolated as a tobacco labdane besides ds-abienol.4* As the extention of the studies on the microbial transformation of labdanes in tobacco, the bioconversion of sclareol by the same bacterium, JTS-162, was investigated. This paper reports the isolation and identification of the transformation products and the biotransformation pathway of sclareol by the bacterium JTS-162. MATERIALS AND METHODS Chemicals. Sclareol was provided by Takasago Perfumery Co., Tokyo. All other reagents used were commercial products of high quality grade. Microorganism. The bacterium JTS-1 62, first isolated as a m-abienol transformable microorganism,3* was used in this study. Thestock culture wasmaintained on L-agar slant and stored at 4°C.

DIVERSITY OF THE DITERPENES IN THE LEAVES OF Xylopia laevigata (Annonaceae) AND THEIR CYTOTOXICITIES

“…The phytochemical investigation of the hexane extract from the leaves of X. laevigata (Annonaceae) yielded six compounds (Figure 1), including one uncommon ent-kaurene diterpenoid ent-7β-acetoxy-16β-hydroxy-kaurane (3), in addition to other five isolated compounds, abieta-7,13-dien-3-one (1), 26 spathulenol (2), 24 13-hydroxy-ent-labda-8,14-dien-18-oic acid (4-epi-cupressic acid) (4), 27 (−)-kaurane-7β,16α-diol (powerol) (5), 28 and 8,20-epoxy-13-hydroxy-ent-labda-14-en-18-oic acid (labdorffianic acid B) (6). 29 Compound 3 was obtained as a white amorphous powder with the molecular formula C 22 25 The signals at δ H 2.05 (s, 3H) and δ H 4.62 (dd, J = 2.8 and 2.9 Hz, 1H) revealed the presence of an acetoxy group and an oxygenated carbon in the structure, respectively.…”

“…According to previously published literature data, 28 only some 1 H NMR resonances were described for this compound, which enabled us to extensively revise 1D and 2D NMR data and unequivocally assign the chemical shifts of hydrogen and carbon atoms (Table 1), and its relative configuration. The isolated compounds: abieta-7,13-dien-3-one (1), 26 spathulenol (2), 24 13-hydroxy-ent-labda-8,14-dien-18-oic acid (4), 27 (−)-kaurane-7β,16α-diol (5), 28 and 8,20-epoxy-13-hydroxy-ent-labda-14-en-18-oic acid (6) 29 were identified by comparison of their NMR and MS data with those previously reported in the literature. Nevertheless, compounds 1, 4, and 6 have been described a long time ago and their published NMR data was incomplete ( 1 H and 13 C NMR).…”

“…As well as showing some ambiguities in the scalar coupling constants, most of them not been previously assigned. 26,[27][28][29] Therefore, the complete and unequivocal NMR data for these diterpenes were reviewed according to the 1D and 2D NMR experiments (Tables 1 and 2).…”

A new pathway in the microbial transformation of cis-abienol by Nocardia restricta JTS-162.

“…restricta JTS-162. In the sclareol transformation by the same bacterium, 5) it was indicated that the addition of some metabolic inhibitors, such as o^a'-dipyridyl, was useful for the accumulation of new transformation products. In this study, we applied this method for the transformation of c/s-abienol to obtain new transformation products.…”

Plasmid-determined Transformation ofcis-Abienol and Sclareol inNocardia restrictaJTS-162

“…The extract was analysed by TLC and GC-MS. 17,14-dien-18-oic acid] were obtained as the transformation products from sclareol with bacterium JTS-162. 2 ) Ten mg of each compound (cisabienol, sclareol or their transformation products) was added to 5 ml of medium-A or medium-B containing the cured strain (about 108/ml) and 0.5mg of Tween-60. After 60 hr incubation, the resulting culture was acidified to pH 3.0 and extracted with ethyl acetate.…”