Sophon Roengsurnran*, Amorn Petsoin*, Nattays Ngamrojanavanich*, Thanatip Rugsilp*, Pailin Sittiwicheanwong*, Prapas Khorphueng*, Wicha Cherdshewasartt*, and Chaiyo Chaichantipyuth***
*Department of Chemistry, “Department of Biology, Faculty or Science, ***Department of Pharmacognocy, Faculty of Pharmaceutical Sciences, Chulalongknm University, Bangkok 10330. Thailand.
ABSTRACT
Flavonoid (3, 7, 3′-Trihydroxy-4′-methoxyflavone) (1) and flavonoid glycoside (3, 3′-dihydroxy-4′, methoxyflavone-7-O-B -D-glucopyranoside) (2) were isolated from the roots of Butea superba Roxb. The structures were determined on the basis of spectral analysis, including 2D- NMR techniques. These compounds show strong inhibitory effects on cAMP phosphodiesterase.
INTRODUCTION
Butea superba Roxb. is a herb in the Family Papilionaceae and has the characteristics of being a crawler that wraps itself around large tress. One branch has 3 leaves, the flowers are of a yellowish orange color and the plant grows out in the open. The long roots of the plant is buried under the ground like the roots of a yam. This type of plant reproduces through seeds and the separation of its roots. This plant can be found growing in forests in the northern regions, in the eastern regions and along Kanchanaburi Province. The roots and stem of the plant are medicines for strength and power. In additionl the roots and stem of the plant are considered to help increase the male sexual performance. Thus, this plant has become to be known as one type of miracle herb. Since Burea superba Roxb helps to enhance the human health, this was considered to be an influential factor in separating the chemical constituents of this herb. The bioactivity of each constituent was tested, especially the inhibitory effect towards cAMP phosphodiesterase, which has an effect in the controlling the body and controlling a wide number of diseases [1]. Therefore, it was planned to conduct research on the bioactivity of these chemical constituents in order to prove whether this herb is actually capable of enhancing the human health as stated beforehand.
KEYWORDÂ Â Â Â Butea superba, Flavonoid, Flavonoidglycoside, cAMP phosphodiesterase inhibition
EXPERIMENTAL
General Experimental Procedures.
All commercial grade solvents were distilled prior to use. Melting points were determined on a Fisher-Johns melting point apparatus and are reported uncorrected. The optical rotation was determined on a JASCO DIP-370 digital polarimeter. Measurements of UV spectra were carried out on a Milton Roy Spectronic 3000 Array UV/VIS spectrophotometer. IR spectra were recorded on a Perkin-Elmer model 1760X FT-IR spectrophotometer. Spectra of solid samples were recorded as KBr pellets 1H and C NMR spectra were recorded at 500.00 and 125.65 MHz, respectively, on a JEOL JNM-A500 NMR spectrometer. LREIMS were obtained with a Fisons Instruments model Trio 2000 mass epectrometer at 70 eV.
Plant Materials
The roots of Butea Superba Roxb. was collected from Amphur Muang, Lampang Province, Thailand in May 1997. Botanical identification was claimed through comparison with a voucher specification No. BKF 70163 in the herbarium collection of Royal Forest Department of Thailand.
Extraction and Isolation
The powdered sun dried roots (16.0 kg) of Butea Superba was repeatedly extracted with MeOH (5×10 L). Thc MeOH extracts were filtered and evaporated under reduced pressure to obtain a dark-red gummy residue (106.0 g) of MeOH crude extract. This MeOH crude extract was subsequently re-extracted with hexane and then CHCl3 to leave the final insoluble residue (72.0 g). The hexane and CHCL3 extract fractions were evaporated under reduce pressure until becoming dry to give a hexane crude extract (21.0 g) and CHCI3 crude extract (12.0 g), respectively. A portion (12.0 g) of CHCI3 crude extract was subjected to silica gel column chromatography using a gradien elution with CHCI3 and MeOH in a stepwise fashion. Compound 1 was eluted with 5% MeOH in CHCL3. Similar fractions were combined and the solvent was removed under reduced pressure to give compound 1 (135.0 mg) after recrystallization from MeOH and CHCl3. The final residue (72.0 g) was separated by column chromatography on Silica gel using gradient elution with increasing amounts of MeOH in CHCl3. Compound 2 (60.0 mg) was collected from 10% of MeOH in CHCI3 fraction, after recrystallization from MeOH and CHCI3.
Flavonoid (3, 7′ 3 -Trihydroxy- 4′- methoxyflavone) (compound 1): pale yellow needle crystal, mp 258 – 260°c (d), (found: C, 64.0; H, 3.9, C14H12O6 required: C=64.0; H=4.0); UV λmax EtOH nm 254, 316 and 365; IR νKBr max cm-1; 3340 – 3000, 2940, 1650, 1594, 1575, 1500, 1450, 1380, 1260, 1090, 1020, 790; 1H and 13C-NMR Table 1; EIMS m/z (rel.int.) 300[M] (25), 282 (30), 268 (100), 253 (25), 132 (60).
Flavonoid glycoside (3,5′-Dihydroxy- 4′- methoxyflavone-7-O-B-D-glucopyranoside)(compound 2); white amorphous; mp 210-212 C, (found: C, 57.0; H, 4.5, C22H22O11 requires: C, 57.0; H, 4.8); [α]25D +9.5 L (e 1.05, MeOH); UV λmax EtOH nm 267, 290 and 355; νKBr Max em ; 3600-3100, 2900, 150, 1550, 1450, 1300, 1260, 1060-1030, 891, 800; H
