The phytochemical investigation from n-hexane extract of the lichen Roccella montagnei

Nội dung text: The phytochemical investigation from n-hexane extract of the lichen Roccella montagnei

1. Science & Technology Development Journal, 24(2):1933-1937 Open Access Full Text Article Research Article The phytochemical investigation from n-hexane extract of the lichen Roccella montagnei Duong Thuc Huy1, Nguyen Thi Hoai Thu2,* ABSTRACT Introduction: Roccella montagnei is widely distributed in subtropical regions. As the continuous study on the hexane extract of Roccella montagnei lichen, the isolation and structural determina- Use your smartphone to scan this tion of five compounds were addressed. Method: The crude extract was obtained from the dried QR code and download this article lichen powder's extraction at room temperature. The n-hexane, n-hexane-ethyl acetate, and ethyl acetate extracts were obtained by the liquid-liquid partition method. The organic compounds were isolated from n-hexane extract by silica gel and Sephadex LH-20 column chromatography. Their chemical structures were identified by the NMR and HR-ESI-MS data analysis and the comparison of their NMR data with the published data. Results: Five compounds were isolated and chem- ically structural identified, consisting of 3β -hydroxy-7α -methoxystigmast-5-ene (1), sekikaic acid (2), lichenxanthone (3), (+)-6,8-dihydroxy-3-propyl-3,4-dihydroisocoumarin (4), and ar-turmerone (5). Conclusion: To the best of our knowledge, except 3 which was reported from this species for the first time, four isolated compounds left did not known to be present in Roccella genus before. Key words: Roccella montagnei, lichen, sterol, aromatic compound INTRODUCTION Minh City and the Institute of Drug Quality Control Ho Chi Minh city. Rocclella genus distributes in the subtropical regions, Mediterranean and mainly in the Northern hemi- 1Department of Chemistry, Ho Chi Minh Plant material 1 City University of Education, Ho Chi sphere . Roccella montagnei species is commonly The lichen Roccella montagnei was collected at Tuy Minh City, Vietnam found along the Coromandel coast and in the man- Phong District, Binh Thuan Province, Vietnam, in 2Faculty of Basic Sciences, University of grove forest in Indian and in the South of Vietnam 2. June 2018. The scientific name of the lichen was au- Medicine and Pharmacy at Ho Chi The previously chemical investigations on this species Minh City, Ho Chi Minh City, Vietnam thenticated by Dr. Holger Thỹs, Life Science De- showed the presence of depside, depsidone, quinone, partment, The Natural History Museum, Cromwell Correspondence sterol, usnic acid derivatives, and phenolic com- Road, SW7 5BD London, England, UK. In addition, Nguyen Thi Hoai Thu, Faculty of Basic pounds 3–5. The bioactive assessments on extracts and a voucher specimen (No US–B024) was deposited in Sciences, University of Medicine and isolated compounds from this species revealed anti- Pharmacy at Ho Chi Minh City, Ho Chi the Herbarium of Department of Organic Chemistry, Minh City, Vietnam inflammatory, antimicrobial, anti-arthritic, antioxi- Faculty of Chemistry, University of Science, VNU dant, and anticancer activities 2,4,6,7. The phytochem- Email: nguyenthihoaithu@ump.edu.vn HCM. ical investigation on this species was further studied History • Received: 2021-05-09 on n-hexane extract led to the isolation and structural Extraction and isolation • Accepted: 2021-05-10 elucidation of 5 compounds. • Published: 2021-05-13 The fresh lichen Roccella montagnei (7.5 kg) was MATERIALS AND METHODS cleaned, air-dried, and ground into powder. Then, DOI : 10.32508/stdj.v24i2.2528 876.8 g of crude extract was prepared using the General experimental procedures above lichen powder in ethanol (3x10L) at room tem- NMR spectra were recorded on Bruker Avance at 500 perature. Next, this crude extract was applied to MHz for 1H-NMR and 125 MHz for 13C-NMR or liquid-liquid partition step with n-hexane (100%), Copyright on Bruker Avance III at 400 MHz for 1H-NMR and n-hexane:ethyl acetate (1:1, v/v), and ethyl acetate â VNU-HCM Press. This is an open- 100 MHz for 13C-NMR. In addition, the HR-ESI- (100%) in turn to afford extracts, including n-hexane access article distributed under the terms of the Creative Commons MS spectra were acquired on a Bruker MicrOTOF-Q (H, 200.9 g), n-hexane:ethyl acetate (1:1) (H:EA, 225.5 Attribution 4.0 International license. 10187. The NMR and MS spectra were done at the g), and ethyl acetate (EA, 313.6 g). Center Analysis Laboratory of the University of Sci- The n-hexane extract was subjected to silica gel ence, Vietnam National University (VNU)–Ho Chi column chromatography which was eluted with n- Cite this article : Huy D T, Thu N T H. The phytochemical investigation from n-hexane extract of the lichen Roccella montagnei. Sci. Tech. Dev. J.; 24(2):1933-1937. 1933
2. Science & Technology Development Journal, 24(2):1933-1937 hexane: ethyl acetate (13:1) to give seven sub- Lichenxanthone (3): White crystal. The 1H-NMR fractions (coded, PH1-PH7). PH2 (43.7 g) was ap- (CDCl3): δ H 6.30 (d, 2.0 Hz, H-2), 6.34 (d, 2.4 Hz, plied to Sephadex-LH20, eluted with methanol to ob- H-4), 6.69 (d, 2.4 Hz, H-5), 6.67 (d, 2.0 Hz, H-7), 2.85 tain five sub-fractions (coded, 2.1-2.5). Then, two (s, H-9), 3.87 (s, 3-OCH3), 3.90 (s, 6-OCH3), 13.39 (s, compounds, 1 (10 mg) and 5 (8.7 mg) were isolated 1-OH). from sub-fraction 2.2 (4.5 g) by the silica gel col- (+)-6,8-Dihydroxy-3-propyl-3,4- umn chromatography method, eluted with the sol- dihydroisocoumarin (4): Colorless needle crystal, α 20 vent system of n-hexane:chloroform: ethyl acetate [ ]D = + 170 (c 0.1, MeOH). HR-ESI-MS: m/z + 1 δ (15:1:1). Next, PH4 (6.7 g) was separated into four 245.0794 [M+Na] . The H-NMR (CDCl3): H 4.53 sub-fractions 4.1 to 4.1 by the Sephadex-LH20 col- (m, H-3), 2.82 (dd, 4.4, 16.4 Hz, H-4a), 2.88 (dd, 10.4, umn chromatography, eluted with methanol. After- 16.0 Hz, H-4b), 6.31 (brs, H-5), 6.21 (brs, H-7), 1.68 ′ ′ ward, sub-fractions 4.3 (2.4 g) was subjected to the C- (m, H-1 a), 1.88 (dddd, 5.2, 7.6, 10.0, 13.6 Hz, H-1 b), ′ ′ 18 reversed-phase silica gel column chromatography, 1.49 – 1.58 (m, H-2 ), 0.97 (t, 7.2 Hz, H-3 ), 6.00 (brs, 6-OH), 11.20 (s, 8-OH). eluted with the solvent system of Me: H2O (15:1) to α 20 obtain 3 (11 mg) and 4 (7 mg). The same procedure Ar-turmerone (5): Yellow solid, [ ]D = 0 (c 0.2, 1 δ was applied to sub-fraction PH7 (50.8 g) to afford 2 MeOH). The H-NMR (CDCl3): H 2.31 (s, H-1), (9.5 mg). 7.10 (s, H-3/H-7; H-4/H-6), 3.29 (m, H-8), 2.72 (dd, 8.0, 16.4 Hz, H-9a), 2.60 (dd, 8.0, 16.4 Hz, H-9b), 6.02 RESULTS (s, H-11), 2.10 (d, 1.6 Hz, H-13), 1.85 (d, 1.6 Hz, H- 13 From the n-hexane extract of the lichen Roccella mon- 14), 1.24 (d, 6.8 Hz, H-15). The C-NMR (CDCl3): δ tagnei, collected at Binh Thuan Province, five com- C 21.1 (C-1), 135.9 (C-2), 129.2 (C-3/C-7), 126.8 (C- 4/C-6), 143.5 (C-5), 35.4 (C-8), 52.8 (C-9), 200.1 (C- pounds, 1 (10 mg), 2 (9.5 mg), 3 (11 mg), 4 (7 mg), 10), 124.2 (C-11), 155.3 (C-12), 20.9 (C-13), 27.9 (C- and 5 (8.7 mg), were isolated. Their physical proper- 14), 22.1 (C-15). Selected HMBC correlations: see ties and spectroscopic data were performed as follows. Figure 2. 3β-Hydroxy-7α-methoxystigmast-5-ene (1): Col- 1 δ orless powder. The H-NMR (CDCl3): H 3.62 (tt, DISCUSSION 5.0, 11.0 Hz, H-3), 2.36 (ddd, 1.8, 5.0, 13.0, H-4a), Compound 1 was isolated as a colorless powder. The 2.30 (ddt, 1.5, 11.0, 13.0, H-4b), 5.74 (dd, 2.0, 5.0, 1H-NMR spectrum showed an olefinic methine pro- H-6), 3.29 (brt, 4.0, H-7), 1.96 (dt, 3.5, 12.5, H-12), ton signal at δ H 5.74 (dd, 2.0, 5.0, H-6), two oxy- 0.66 (s, H-18), 0.98 (s, H-19), 0.92 (d, 6,5 Hz, H-21), genated methine protons at δ H 3.62 (tt, 5.0, 11.0 Hz, 0.81 (d, 7.0 Hz, H-26), 0.83 (d. 6.5 Hz, H-27), 0.86 13 H-3) and 3.29 (brt, 4.0, H-7), a methoxy proton sig- (t, 7.5 Hz, H-29), 3.35 (s, -OCH3). The C-NMR nal at δ H 3.35 (s, -OCH3) and the rest proton signals (CDCl ): δ 36.9 (C-1), 31.6 (C-2), 71.6 (C-3), 42.5 3 C resonating at high magnetic field including two sin- (C-4), 146.3 (C-5), 120.9 (C-6), 74.1 (C-7), 37.4 (C-8), glets (δ H 0.66 and 0.98), three doublets (δ H 0.92, 0.81, 42.9 (C-9), 37.6 (C-10), 21.0 (C-11), 39.2 (C-12), 42.3 and 0.83) and a triplet (δ H 0.86) methyl signals which (C-13), 49.2 (C-14), 24.4 (C-15), 28.4 (C-16), 55.9 (C- characterized for the stigmastane skeleton. It corre- 17), 11.6 (C-18), 18.4 (C-19), 36.3 (C-20), 19.0 (C- sponded to the presence of a methoxy carbon and 29 21), 34.1 (C-22), 26.2 (C-23), 46.0 (C-24), 29.4 (C- carbons of the stigmastane. Two olefinic carbon sig- 25), 19.2 (C-26), 20.0 (C-27), 23.3 (C-28), 12.2 (C-29), nals resonated at δC 146.3 and 120.9 were a quater- 56.9 (-OCH3). nary olefinic carbon (=C<, C-5) and a methine carbon 1 Sekikaic acid (2): Colorless solid. The H-NMR (=CH-, C-6), respectively, in stigmast-5-ene as usual. δ (CDCl3): H 6.38 (s, H-3), 6.38 (s, H-5), 2.99 (m, H- The proton H-3 showed the large coupling constant 8), 1.74 (m, H-9), 0.94 (t, 7.2 Hz, H-10), 3.83 (s, 4- value of 11.0 Hz with both axial protons H-2 and H- ′ ′ ′ OCH3), 6.43 (s, H-5 ), 2.97 (m, H-8 ), 1.64 (m, H-9 ), 4, which approved the β-configuration of the hydroxy ′ ′ 13 1.00 (t, 6.8 Hz, H-10 ), 3.89 (s, 4 -OCH3). The C- group at C-3. Pettit and co-worker8 reported that δ NMR (Acetone-d6): C 105.5 (C-1), 165.8 (C-2), 99.7 the 7-methoxystigmast-5-ene compounds displayed a (C-3), 165.4 (C-4), 111.4 (C-5), 149.0 (C-6), 169.3 (C- large coupling constant of 8.2 Hz of proton H-7α and 7), 39.2 (C-8), 26.1 (C-9), 14.6 (C-10), 55.9 (4-OCH3), a small coupling constant of 4.8 Hz of proton H-7β. ′ ′ ′ ′ 107.0 (C-1 ), 157.3 (C-2 ), 125.6 (C-3 ), 156.2 (C-4 ), The compound 1 revealed the signal at δ H 3.29 (brt, ′ ′ ′ ′ 106.7 (C-5 ), 146.8 (C-6 ), 174.2 (C-7 ), 39.2 (C-8 ), 4.0) of H-7, demonstrating the α-configuration of the ′ ′ ′ 25.7 (C-9 ), 14.6 (C-10 ), 56.5 (4 -OCH3). Selected 7-methoxy group. Based on the above analysis and HMBC correlations: see Figure 2. the good compatibly NMR data with those published 1934
3. Science & Technology Development Journal, 24(2):1933-1937 Figure 1: The chemical structures of isolated compounds 1-5 in the literature 8, 1 was suggested to be 3β-hydroxy- (s, H-9) was belonged to a methyl group connected to 7α-methoxystigmast-5-ene. a benzene ring. Besides, the NMR data of 3 showed Compound 2 was isolated as a colorless solid. The 1H- highly relevant to the published data 10, 3 was thus de- NMR spectrum displayed aromatic proton signals at termined as lichenxanthone. δ H 6.38 (2H, s, H-3/H-5) of a tetra-substituted ben- Compound 4 was isolated as a colorless needle crys- ′ zene ring and 6.43 (s, H-5 ) of a penta-substituted one. tal. The HR-ESI-MS of 4 showed the sodiated ion peak δ + Two methoxy proton signals were observed at H 3.83 at m/z 245.0794 [M+Na] (calcd. for C12H14O4Na, ′ (s, 4-OCH3), 3.89 (s, 4 -OCH3). At the higher mag- 245.0790) which deduced its molecular formula to be 1 netic field, it showed signals of two n-propyl moi- C12H14O4. The H-NMR spectrum displayed a sin- δ eties at H [2.99 (m, H-8), 1.74 (m, H-9), 0.94 (t, glet proton signal at δ 11.20 (s, 8-OH) of a phe- ′ ′ H 7.2 Hz, H-10)] and [2.97 (m, H-8 ), 1.64 (m, H-9 ), ′ nolic hydroxy group which was chelated to an or- 1.00 (t, 6.8 Hz, H-10 )] which were further identi- tho-carbonyl group. Two broad-singlet proton sig- fied by the HMBC cross-peaks as shown in Figure 2. nals at 6.31 (brs, H-5) and 6.21 (brs, H-7) suggested 13 The C-NMR spectrum showed 22 signals consist- the presence of a 1,2,3,5-tetra-substituted benzene ing of twelve signals of two benzene rings from 99.7 ring. A very broad-singlet signal integrated one pro- δ to 165.8 ppm, two carboxyl carbons at C 169.3 (C-7) δ ′ ton at H 6.00 (brs, 6-OH) was deduced to a hydroxy and 174.2 (C-7 ), two methoxy carbons at δC 55.9 (4- ′ group which did not exist the intramolecular hydro- OCH3) and 56.5 (4 -OCH3), and six final carbon sig- gen bond. There was a multiplet signal at δ H 4.53 (H- nals from 14.6 to 39.2 ppm belonging to two n-propyl 3) of an oxygenated methine group in the magnetic chains. The position of two methoxys were C-4 and zone of protons on the carbon attached to the single- C-4’,which were confirmed by HMBC correlations of bonded oxygen. Signals of two non-equivalent pro- the methoxy protons to carbons at δC 165.4 (C-4) and ′ tons of a methylene group deshielded at δ 2.82 (dd, 156.2 (C-4 ). The HMBC correlations of H-8 to car- H 4.4, 16.4 Hz, H-4a) and 2.88 (dd, 10.4, 16.0 Hz, H-4b) bon C-1, C-5, and C-6, of H-8’ to carbons C-1’, C- due to the attachment to sp2 quaternary carbon and a 5’, and C-6’ determined the positions of two n-propyl chiral methine group. At highest magnetic field, the groups at C-6 and C-6’. All other HMBC correlations observation of a triplet signal, integrated three pro- confirmed the chemical structure of 2. Additionally, ′ the comparison of NMR data of 2 with the published tons at 0.97 (t, 7.2 Hz, H-3 ) belonged a methyl group 9 which was adjacent one methylene group. Four re- data showed good compatibility; therefore, 2 was as- ′ maining protons at δ H 1.68 (1H, m, H-1 a), 1.88 (1H, signed as sekikaic acid. ′ 1 dddd, 5.2, 7.6, 10.0, 13.6 Hz, H-1 b), 1.49 (1H, m, H- Compound 3 was isolated as a white crystal. The H- ′ 2’a), and 1.58 (1H, m, H-2 b) were deduced the pres- NMR spectrum showed a signal at δ H 13.39 (s, 1- OH) of the proton of a phenolic hydroxy group which ence of two methylene groups. Based on the above in- was chelated to an ortho-carbonyl group, two meta- formation and the good compatibility of its NMR data 11 doublet signals which had the multiplet skewing effect with those published in the literature , along with its α 20 together at δ H 6.30 (d, 2.0 Hz, H-2), 6.34 (d, 2.4 Hz, dextrorotatory activity [ ]D = + 170 (c 0.1, MeOH), H-4) of a tetra-substituted benzene ring, two other 4 was determined as (+)-6,8-dihydroxy-3-propyl-3,4- meta-doublet signals δ H 6.69 (d, 2.4 Hz, H-5), 6.67 (d, dihydroisocoumarin. 2.0 Hz, H-7) of the second tetra-substituted benzene Compound 5 was isolated as a yellow solid. The 1H- ring. The moderate magnetic zone revealed signals NMR spectrum of 5 displays a singlet proton sig- of two methoxy groups at δ H 3.87 (s, 3-OCH3) and nal integrated four-protons at δ H 7.10 ( , H-3/H-7; 3.90 (s, 6-OCH3). The final proton signal at δ H 2.85 H-4/H-6) para-disubstituted benzene ring, a singlet 1935
4. Science & Technology Development Journal, 24(2):1933-1937 Figure 2: Selected HMBC correlations of 2 and 5 olefinic proton at δ H 6.02 (1H, s, H-11) of a me- CONCLUSION thine group =CH- attached to two quaternary car- From the n-hexane extract of the lichen Roccella mon- bons. At the high magnetic field, the proton spectrum tagnei, five compounds were isolated consisting of δ displayed signals at H 2.10 (d, 1.6 Hz, H-13) and 1.85 a sterol (3β-hydroxy-7α-methoxy-stigmast-5-ene), a (d, 1.6 Hz, H-14), which possessed HMBC correla- depside (sekikaic acid), a xanthone (lichenxanthone), δ tions to the same olefinic carbons at C 124.2 (C-11), a coumarin derivative ((+)-6,8-dihydroxy-3-propyl- 155.3 (C-12). These signals suggested the presence of 3,4-dihydroisocoumarin), and an ar-turmerone (5). -CH=C(CH3)2 moiety. A methyl proton signal res- Their chemical structures were elucidated by NMR, onated at 2.31 (s, H-1) was suggested to attach to the MS spectroscopic data analysis, optical rotations, and benzene ring (as para-CH3C6H4-), which was further the comparison to the published data. Four isolated confirmed by HMBC cross-peaks of this proton signal compounds 1, 2, 4, and 5 were reported to presence in to aromatic carbons at δC 135.9 (C-2) and 129.2 (C- the Roccella genus for the first time while 3 had been 3/C-7). A proton signal appearing as a doublet, in- already isolated from other species of this genus. The tegrated three-protons at 1.24 (d, 6.8 Hz, H-15) was ongoing studies on this species are in progress. assigned to the methyl group attached to the other ABBREVIATIONS methine group. This methyl proton signal showed HR-ESI-MS: High resolution-Electrospray HMBC correlations to a quaternary aromatic carbon ionization-Mass spectrometry C-5 at 143.5 (C-5), a methine carbon C-8 (35.4), and 1 H-NMR: Proton nuclear magnetic resonance a methylene carbon C-9 (52.8), which demonstrated 13 C-NMR: Carbon-13 nuclear magnetic resonance the presence of CH -CH(C H CH )-CH - fragment. 3 6 4 3 2 HSQC: Heteronuclear single quantum coherence The 13C-NMR spectrum showed a ketone carbon sig- HMBC: Heteronuclear multiple bond correlation nal shielded at 200.1 (C-10), deduced to be the ke- s: singlet tone group conjugated to the double bond. It cor- brs: broad singlet responded to the sole quaternary olefinic carbon C- d: doublet 12 shifted to the higher frequency at 155.3 ppm. All t: triplet the rest of HMBC correlations supported the chem- m: multiplet ical structure as shown. Additionally, the compari- son of its NMR data to those reported in the liter- COMPETING INTEREST ature 12 gave further evidence to confirm the chem- The authors declare no competing financial interest. ical structure of 5 as ar-turmerone. The optical ro- α 20 AUTHORS’ CONTRIBUTION tation value of [ ]D = 0 suggested 5 to be a racemic mixture of ar-turmerone. Ar-turmerone was known Duong T.H contributed to conducting experiments, as the major bioactive compound of Curcuma longa acquisition of data, and interpretation of data. species and possessing anti-inflammatory and neuro- Nguyen T. H. T interpreted NMR and MS data as well protective property 13. as gave final approval of the manuscript to be submit- ted. 1936
5. Science & Technology Development Journal, 24(2):1933-1937 Corresponding author: Dr. Nguyen Thi Hoai Thu, 6. Vijayakumar CS, Viswanathan S, Reddy MK, Parvathavarthini S, University of Medicine and Pharmacy at Ho Chi Kundu AB, Sukumar E. Anti-inflammatory activity of (+)-usnic acid. Fitoterapia. 2000; 71:564-566;Available from: Minh City, 217 Hong Bang Str., District 5, Ho Chi org/10.1016/S0367-326X(00)00209-4. Minh City. Email: nguyenthihoaithu@ump.edu.vn or 7. Mishra T, Shukla S, Meena S, Singh R, Pal M, Upreti KD, Datta hoaithudhyd@gmail.com D. Isolation and identification of cytotoxic compounds from a fruticose lichen Roccella montagnei and it’s in silico docking study against CDK-10. Revista Brasileira de Farmacognosia. ACKNOWLEDGMENT 2017; 27(6);Available from: This research was supported by NAFOSTED under 07.006. 8. Pettit GR, Numata A, Cragg GM, Herald DL, Takada T, Iwamoto grant number 104.01-2019.45. C, Riesen R, Schmidt JM, Doubek DL, Goswami A. Isolation and structures of schleicherastatins 1-7 and schleicheols 1 and 2 REFERENCES from the Teak forest medicinal tree Schleichera oleosa. Jour- nal of Natural Product. 2000; 63:72-78;PMID: 10650082. Avail- 1. Prashanth SR, Bharath P, Valarmathi R, Balaji P, Parida able from: A, Hariharan GN. Species status and relationship between 9. Lai D, Odimegwu DC, Grunwald T, Esimone C, Proksch P. Roccella montagnei and Roccella belangeriana using DNA Phenolic compounds with in vitro activity against respiratory sequence data of nuclear ribosomal internal transcribed syncytial virus from the Nigerian lichen Ramalina farinacea. spacer region. Journal of Plant Biochemistry & Biotechnol- Planta Medica. 2013; 79:1440-1446;PMID: 23970423. Avail- ogy. 2008; 17(1):91-94;Available from: able from: BF03263267. 10. Brandóo LFG, Alcantara GB, Matos M de FC, Bogo D, Freitas D 2. Balaji P,Bharath P,Satyan RS, Hariharan GN. In vitro antimicro- dos S, Oyama NM, Honda NK. Cytotoxic evaluation of pheno- bial activity of Roccella montagnei thallus extracts. Journal of lic compounds from lichens against melanoma cells. Chem- Tropical Medicinal Plants. 2006; 7(2):169-173;. ical and Pharmaceutical Bulletin. 2013; 61(2):176-183;PMID: 3. Duong TH, Huynh BLC, Chavasiri W, Chollet-Krugler M, 23207680. Available from: Nguyen VK, Nguyen THT, Hansen PE, Le Pogam P, Thỹs H, 00739. Boustie J, Nguyen KPP. New erythritol derivatives from the 11. Xie T, Zheng C, Chen K, He H, Gao S. Asymmetric total syn- fertile form of Roccella montagnei. Phytochemistry. 2017; thesis of the complex polycyclic xanthone FD-594. A Jour- 137:156-164;PMID: 28222890. Available from: nal of the German Chemical Society. 2020; 59(11):4360- 10.1016/j.phytochem.2017.02.012. 4364;PMID: 31943607. Available from: 4. Tatipamula VB, Vedula, GS, Sastry AVS. Chemical and phar- 1002/anie.201915787. macological evaluation of manglicolous lichen Roccella mon- 12. Dhingra OD, Jham GN, Barcelos RC, Mendonỗa FA, Ghiviriga tagnei Bel em. D. D. Awasthi. Future Journal of Pharmaceuti- I. Isolation and identification of the principal fungitoxic com- cal Sciences. 2019; 5:8;Available from: ponent of Turmeric essential oil”, Journal of Essential Oil Re- s43094-019-0009-6. search. 2007; 19:387-391;Available from: 5. Mallavadhani UV, Sudhakar AVS. Roccellatol, a new β- 1080/10412905.2007.9699312. orcinol based metabolite from the lichen Roccella mon- 13. Hucklenbroich J, Klein R, Neumaier B, Graf R, Fink GR, tagnei. Natural Product Research. 2017; 32:268-274;PMID: Schroeter M, Rueger MA. Aromatic-turmerone induces neural 28726494. Available from: stem cell proliferation in vitro and in vivo. Stem Cell Research 2017.1353508. & Therapy. 2014; 5:100;PMID: 25928248. Available from: https: //doi.org/10.1186/scrt500. 1937