Gaikwad Switi Balkrushna1*, G. Krishna Mohan2, Chaudhari Sanjay Ravindra1
1Rasiklal M. Dhariwal Institute of Pharmaceutical Education & Research, Chinchwad, Pune, Maharashtra
2Centre for Pharmaceutical Sciences, IST, Jawaharlal Nehru Technological University Hyderabad, Telangana *Corresponding Author E-mail: email@example.com
Thespesia populnea (Linn.) Sol. ex Correa (Malvaceae) is commonly known as ‘Portia tree’. Plant is well known for its medicinal importance. In the present study, attempt has been made to characterise the oil isolated from leaves of T. populnea. The pale yellow color oil was isolated from the n- hexane fraction of total methanolic extract of leaves of T. populnea by column chromatography. Isolated oil was characterised by FT-IR, 1H NMR (500 MHz, CDCl3), 13C NMR (125 MHz, CDCl3), and GC-MS analysis. From the structural data and its comparison with reported literature, isolated compound was identified and confirmed as Phytol. This is a first report on isolation of acyclic diterpene alcohol from the Thespesia populnea Linn plant.
Thespesia populnea (Linn.) Sol. ex Correa (Malvaceae) is commonly known as ‘Portia tree’. It is a large avenue tree founds in coastal areas of the Indian and Pacific oceans, throughout Oceania and also grows well in tropical and warm subtropical climate1. The medicinal importance of this plant is mentioned in famous primordial texts of Ayurveda such as Dravyaguna2. Flavonoids, glycosides, and phytosterols are major constituents of T. populnea. Leaves contain lupeol, β-sitosterol, lupenone, quercetin, ferulic, syringic, and melilotic acid 3, 4.
New mansonone, 7-hydroxy-2,3,5,6-tetrahydro-3,6,9-trimethylnapthol [1,8-b,c] pyran-4,8-dione, mansonone D, E, F, thespesone, thespone have been isolated from Heartwood 5.Gossypol, a potent antifertility agent has been isolated from fruits, and bark of the plant1,6-9. Flowers of the plant are rich in flavonoids like kaempferol, kaempferol-7-glucoside, kaempferol-3- monoglucoside, β-sitosterol, herbacetin. Seeds of the plant are rich with fatty acids like myristic acid, palmitic acid, stearic acid, oleic acid, and linoleic acid. 1,10,11
In this paper, we aimed to report the separation and structural elucidation of isolated oil from the leaves of T. populnea which has not been previously reported from this plant.
Fresh leaves of T. populnea were collected from Ahmednagar district, Maharashtra, India. Authentication of plant was done at Botanical Survey of India, Pune, (Voucher number SWITTHP20). Shade dried leaves were crushed and cold macerated with methanol for 7 days. After 7 days menstrum was filtered and evaporated and kept in desiccator for drying.
Dried total methanol extract of plant was dissolved in methanol and fractionated with n-hexane to produce two different fractions. n-hexane soluble fraction was subjected to column chromatography (250 g silica gel, 60 ´ 4 cm) packed with Silica gel G (60-120#) in n- hexane and gradiently eluted with n- hexane and CHCl3 with different proportion (from 9.5:0.5 upto 0.5:9.5). The oil recovered in the mobile phase n-hexane: CHCl3 (5:5/1:1) which were subjected for thin layer chromatography. The silica gel 60F254 pre-coated plates (Merck TM) were used for TLC. Plate was scanned under HPTLC at 254nm to confirm the presence of spots and then sprayed with anisaldehyde-H2SO4 reagent.12,13
A FT- IR spectrum was recorded with Brucker Alpha T spectrophotometer by KBr pellet technique. The 1H (500 MHz, CDCl3) and 13C NMR (125 MHz, CDCl3) spectra’s were recorded on Brucker Drx NMR using TMS as an internal standard. Electron impact ionization mode was used for fragmentation. HPTLC studies were carried out by using CAMAG HPTLC instrument.
RESULTS AND DISCUSSION:
Boiling Point of oil was found to be 199ºC. Isolated compound was tested for HPTLC scanning to know the number of constituents present in the compound. HPTLC chromatogram showed single spot when sprayed with anisaldehyde-H2SO4 reagent (Figure 1).
Figure 1: HPTLC scan of Phytol
IR spectrum (Figure 2) of isolated oil shows strong absorption bands at 2927cm-1, 2870 cm-1, 1778 cm-1, 1383 cm-1 reveals the presence of C-H stretching in methyl and methylene groups, while O-H stretching absorption band appear at 3333 cm-1. Sharp absorption peak was observed for C-O group at 1004 cm-1, confirms the presence of –OH group. Absorption band observed at 1669 cm-1 confirms C=C group.14-18
Figure 2: FT-IR spectrum of Phytol
1H NMR spectrum (Figure 3) of compound reveals the presence of methyl group at δ 1.01, δ 1.06, δ 1.71 while methylene group has shown the signals at δ1.29, δ 1.33, δ 1.96 and methylene group attached to –OH i.e (CH2OH) has shown shift at δ 4.3 . Hydrogen attached to double bond (ethylene) appears at downfield i.e. at δ 5.39. 14-18
Figure 3: 1H NMR spectrum of Phytol
The 13C NMR spectrum showed presence of CH2 nearer to OH group appeared at δ 59.6 and other aliphatic carbons are present at δ 24.4, δ 37.12, δ 39.9, δ 59.6. Ethylene carbons (C=C) showed signals at δ139.45, 129.42 (Figure 4). 14-18
Figure 4: 13C NMR spectrum of Phytol
In GC-MS analysis ((Figure 5), retention time of the compound was found to be 14 min and in mass fragmentation, peak for M-OH was observed at m/z 278.3 which corresponds to the standard m/z values of Phytol (m/z 278) and base peak was observed at 123 m/z. Molecular ion peak was observed at m/z 296.1 (C20H40O). 11-15
Figure 5: Mass spectrum of Phytol
Figure 6: Structure of Phytol isolated from T. populnea leaves
Above spectroscopic data clearly revels the presence of acyclic diterpene alcohol, from the n-hexane fraction of total methanol extract was identified as i.e. Phytol (Figure 6). This is a first report on isolation of acyclic diterpene alcohol from the T. populnea plant which may be useful for the researchers to explore T. populnea for presence of various phytochemicals and their utility for pharmaceutical industry.
Authors sincerely thank Aurobindo Pharma Ltd Research Centre, Bachupally, Hyderabad and Centre for Environmental Sciences, IST, JNTUH, Hyderabad for spectral analysis studies. Author expresses gratitude to Research and Development Cell, JNTUH, Hyderabad for financial support.
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Received on 08.06.2018 Modified on 18.07.2018
Accepted on 28.07.2018 ©A&V Publications All right reserved