The aim of this study was to investigate the chemical composition of the essential oils of “Covid-Organics” of Madagascar (62%
Artemisia annua and two other undisclosed medicinal plants) used as curative and preventive treatments of Covid-19, to identify its constituent species. The essential oils isolated by hydro-distillation from two samples (curative and preventive) were analyzed by GC-FID and GC-MS. These essential oils (curative and preventive) were mainly dominated by camphor (17.9% and 11.9%, respectively), spathulenol (4.8% and 11.8%, respectively),
α-acorenol (4.3% and 3.7%, respectively), (
E)-
β-caryophyllene (3.4% and 4.2%, respectively), 1,8-cineole (3.1% and 3.6%, respectively), hexadecanoïc acid (3.8% and 3.2%, respectively) and caryophyllene oxide (3.4% and 2.4%, respectively). From the chemical composition, two species were identified,
A. annua characterised by camphor and
Cinnamomumcamphora (Ravintsara) characterised by 1,8-cineole and sabinene. However, we were unable to identify the third species.
Since the end of December 2019, a new coronavirus (Covid-19) with human-to-human transmission and serious human infection was identified. This virus affected many people in a very short time [1] [2] . On January 30, 2020, the Director-General of the World Health Organization declared the Covid pandemic a public health emergency of international concern and issued temporary recommendations under the International Health Regulations [3] .
This pandemic was still ongoing, so there was an urgent need to find new preventive and therapeutic agents as soon as possible. Although specific vaccines and antiviral agents are the most effective methods to prevent and treat viral infection, there are not yet effective treatments that target Covid-19. The development of these treatments could take months or years, which means that a more immediate treatment or control mechanism should be found if possible [4] . Medicinal plants present a potentially valuable resource for this purpose [5] .
Thus, in April 2020, the Malagasy Institute for Applied Research developed an herbal tea composed of 62% Artemisia annua and two other medicinal plants whose names were not revealed that grow in Madagascar (Covid-Organics), claiming preventive and curative properties against Covid-19 [6] . Artemisia annua L. (Asteraceae) is native to China, well known as the source of artemisinin and used in the treatment of the malaria. In addition, its essential oils have several therapeutic properties [7] [8] [9] [10] [11] .
In May, Senegal placed its order for “Covid-Organics”, but the National Scientific Committee demanded that we first carry out in-depth scientific examinations on this product made in Madagascar before possibly using it on patients with coronavirus because reliable botanical, chemical, toxicological and pharmacological data were lacking.
Therefore, the aim of this study was to investigate the chemical composition of the essential oils of “Covid-Organics” to identify its constituent species.
2. Experimental2.1. Plant Material
Samples (two remedies in the form of herbal teas: curative and preventive) were provided by the Pharmacy and Drug Directorate. The two remedies were composed of 62% Artemisia annua and two other medicinal plants whose names were not revealed. The only difference was the dosage: the curative remedy was administered 3 times/day, while the preventive was administered 2 times/day.
2.2. Extraction of Essential Oils
Samples were hydrodistilled (6 h) using a Clevenger-type apparatus according to the method recommended in the European Pharmacopoeia [12] . The yields of essential oils (w/w, calculated on dry weight basis) were given in Table 1.
2.3. Chemical Compositions
The chromatographic analyses were carried out using a Perkin-Elmer Autosystem XL GC apparatus (Walthon, MA, USA) equipped with dual flame ionization detection (FID) system and fused-silica capillary columns, namely, Rtx-1 (polydimethylsiloxane) and Rtx-wax (poly-ethyleneglycol) (60 m × 0.22 mm i.d;
Chemical composition of the essential oils of the two remedies
Na
Compounds
lRIab
RIac
RIpd
Remedies
Curative
Preventive
1
α-thujene
766
922
1023
0.1
0.1
2
α-pinene
936
931
1015
0.4
0.7
3
Camphene
950
943
1066
0.4
0.6
4
Sabinene
973
964
1120
0.6
1.4
5
β-pinene
978
970
1110
0.3
0.5
6
Myrcene
987
980
1159
0.1
0.2
7
p-cymene
1015
1011
1268
0.3
0.8
8
1,8-cineole
1024
1020
1209
3.1
3.6
9
γ-terpinene
1051
1047
1243
0.1
0.2
10
Camphor
1123
1123
1517
17.9
11.9
11
Borneol
1150
1148
1698
0.2
0.8
12
Terpinen-4-ol
1164
1161
1600
2.6
0.1
13
α-terpineol
1176
1179
1700
2.6
2.7
14
Trans-carvyl acetate
1316
1731
0.4
0.6
15
Cis-carvyl acetate
1343
1767
0.2
0.4
16
α-copaene
1379
1379
1488
0.8
0.9
17
(E)-β-caryophyllene
1421
1420
1591
3.4
4.2
19
(E)-β-farnesene
1446
1448
1661
0.2
2.1
18
α-humulene
1455
1456
1665
2.1
5.3
20
α-himachalene
1449
1450
1639
0.9
0.4
21
g-gurjunene
1413
1470
1654
2.1
2.2
22
Germacrene-D
1479
1480
1704
0.9
2.8
23
β-selinene
1486
1483
1712
1.8
2.0
24
Ledene
1491
1494
1695
0.9
1.1
25
Spathulenol
1572
1557
2119
4.8
11.8
26
Caryophyllene oxyde
1570
1569
1980
3.4
2.4
27
Humulene epoxyde II
1602
1601
2044
2.9
3.1
28
1,10-di-epi-cubenol
1615
1608
2031
2.9
5.3
29
α-acorenol
1623
1616
2123
4.3
3.7
30
Cadina-4-en-7-ol
1627
1627
2096
0.4
1.0
31
Hexadecanoïc acid
1962
1947
2886
3.8
3.2
32
Linoleic acid
2123
2123
3176
-
0.6
Hydrocarbon monoterpenes
2.3
4.5
Oxygenated monoterpenes
27.0
20.1
Hydrocarbon sesquiterpenes
13.1
21
Oxygenated sesquiterpenes
22.5
30.5
Other compounds
-
0.6
Total identified (%)
64.9
76.7
Yields (w/w vs dry material)
0.16
0.2
aOrder of elution is given on apolar column (Rtx-1); bRetention indices of literature on the apolar column (lRIa); cRetention indices on the apolarRtx-1 column (RIa); dRetention indices on the polar Rtx-Wax column (RIp).
film thickness 0.25 μm). The oven temperature was programmed from 60 to 230˚C at 2˚C/min and then held isothermally at 230˚C for 35 min: hydrogen was employed as carrier gas (1 mL/min). The injector and detector temperatures were maintained at 280˚C, and samples were injected (0.2 μL of pure oil) in the split mode (1:50). Retention indices (RI) of compounds were determined relative to the retention times of a series of n-alkanes (C5-C30) by linear interpolation using the Van den Dool and Kratz (1963) equation with the aid of software from Perkin-Elmer (Total Chrom navigator). The relative percentages of the oil constituents were calculated from the GC peak areas, without application of correction factors.
Samples were also analysed with a Perkin-Elmer Turbo mass detector (quadrupole) coupled to a Perkin-ElmerAutosystem XL, equipped with fused-silica capillary columns Rtx-1 and Rtx-Wax. The oven temperature was programmed from 60 to 230˚C at 2˚C /min and then held isothermally at 230˚C (35 min): hydrogen was employed as carrier gas (1 mL/min). The following chromatographic conditions were employed: injection volume, 0.2 μL of pure oil; injector temperature, 280˚C; split, 1:80; ion source temperature, 150˚C; ionization energy, 70 eV; MS (EI) acquired over the mass range, 35 - 350 Da; scan rate, 1 s. Identification of the components was based on: (a) comparison of their GC retention indices (RI) on non-polar and polar columns, determined from the retention times of a series of n-alkanes with linear interpolation, with those of authentic compounds or literature data; (b) on computer matching with commercial mass spectral libraries [13] [14] [15] and comparison of spectra with those of our personal library; and (c) comparison of RI and MS spectral data of authentic compounds or literature data.
3. Results and Discussion
The essential oil yields of the two remedies (curative and preventive) were 0.16% and 0.2%, respectively.
Chemical analysis by Gas Chromatography (GC) showed that the two essential oils of the two remedies (curative and preventive) have identical chromatographic profiles. This analysis allowed the identification of 32 compounds representing 64.9 and 76.7%, respectively, of the total chemical compositions. This confirms that the two remedies are made from the same plants. These essential oils (curative and preventive) were mainly dominated by camphor (17.9% and 11.9%, respectively), spathulenol (4.8% and 11.8%, respectively), α-acorenol (4.3% and 3.7%, respectively), (E)-β-caryophyllene (3.4% and 4.2%, respectively), 1,8-cineole (3.1% and 3.6%, respectively), Hexadecanoïc acid (3.8% and 3.2%, respectively) and caryophyllene oxide (3.4% and 2.4%, respectively). Camphor is a characteristic compound of the essential oil of A. annua and its content can be up to 50% in A. annua [7] [8] [16] [17] . It was the main compound of the essential oil of A. annua grown in Senegal [17] . 1,8-cineole was found at significant levels in both essential oils (3.1% and 3.6%, respectively) along with sabinene. These two compounds constitute the chemotype of Ravintsara (Cinnamomum camphora, ct 1,8-cineole and sabinene) from Madagascar [18] [19] [20] [21] [22] . These results show that both remedies contain A. annua and C. camphora. However, we were unable to identify the third species. This hypothesis was confirmed by the capsule form (Artemisinin and essential oil of C. camphora) [23] .
Ravintsara oil is distilled from the leaves of C. camphora belongs to the family Lauraceae in Madagascar. True Ravintsara essential oils contain at least 45% of 1,8-cineole [19] [20] [21] [22] . During the recent outbreak of coronavirus (SARS-CoV-2), Ravintsara oil is found to inhibit the coronavirus in vitro and in vivo due to its antiviral properties [24] [25] . Ravintsara oil is an excellent germ fighter and has antiviral, anti-inflammatory, and anti-spasmodic properties which can calm muscles and soothe coughs [19] [20] [21] [25] .
Conflicts of Interest
The authors declare no conflicts of interest regarding the publication of this paper.
Cite this paper
Tine, Y., Diédhiou, A., Diallo, A., Ndoye, I., Baldé, M., Gaye, C., Ndiaye, B., Wélé, A. and Fall, D. (2023) Chemotaxonomic Study of the Covid-Organics of Madagascar Based on the Chemical Composition of Their Essential Oils. International Journal of Organic Chemistry, 13, 50-56. https://doi.org/10.4236/ijoc.2023.132005
ReferencesKandel, N., Chungong, S., Omaar, A. and Xing, J. (2020) Health Security Capacities in the Context of Covid-19 Outbreak: An Analysis of International Health Regulations Annual Report Data from 182 Countries. The Lancet, 395, 1047-1053. https://doi.org/10.1016/S0140-6736(20)30553-5Zumla, A. and Niederman, M.S. (2020) Editorial: The Explosive Epidemic Outbreak of Novel Coronavirus Disease 2019 (Covid-19) and the Persistent Threat of Respiratory Tract Infectious Diseases to Global Health Security. Current Opinion in Pulmonary Medicine, 26, 193-196. https://doi.org/10.1097/MCP.0000000000000676World Health Organization (2022) Statement on the Second Meeting of the International Health Regulations (2005) Emergency Committee Regarding the Outbreak of Novel Coronavirus (2019-nCoV) https://www.who.int/news/item/30-01-2020-statement-on-the-second-meeting-of-the-international-health-regulations-(2005)-emergency-committee-regarding-the-outbreak-of-novel-coronavirus-(2019-ncov)Jean, S.S., Lee, P.I. and Hsueh, P.R. (2020) Treatment Options for Covid-19: The Reality and Challenges. Journal of Microbiology, Immunology and Infection, 53, 436-443. https://doi.org/10.1016/j.jmii.2020.03.034Boukhatem, M.N. and Setzer, W.N. (2020) Aromatic Herbs, Medicinal Plant-Derived Essential Oils, and Phytochemical Extracts as Potential Therapies for Coronaviruses: Future Perspectives. Plants, 9, Article 800. https://doi.org/10.3390/plants9060800Rakotoarivelo, J. (2022) Covid-Organics: La communauté scientifique sort du silence.Woerdenbag, H.J., Pras, N., Chan, N.G., Bang, B.T., Bos, R., van Uden, W., Van Y, P., Van Boi, N., Batterman, S. and Lugt, C.B. (1994) Artemisinin, Related Sesquiterpenes, and Essential Oil in Artemisia annua during a Vegetation Period in Vietnam. Plantamedica ,60, 272-275. https://doi.org/10.1055/s-2006-959474Juteau, F., Masotti, V., Bessiere, J.M., Dherbomez, M. and Viano, J. (2002) Antibacterial and Antioxidant Activities of Artemisia annua Essential Oil. Fitoterapia, 73, 532-535. https://doi.org/10.1016/S0367-326X(02)00175-2Ćavar, S., Maksimović, M., Vidic, D. and Parić, A. (2012) Chemical Composition and Antioxidant and Antimicrobial Activity of Essential Oil of Artemisia annua L. from Bosnia. Industrial Crops and Products, 37, 479-485.Garcia L.C. ,et al. (2015)A Review of Artemisia annua L.: Its Genetics, Biochemical Characteristics, and Anti-Malarial Efficacy International Journal of Science and Technology 5, 38-46.Libbey, L.M. and Sturtz, G. (1989) Unusual Essential Oils Grown in Oregon II. Artemisia annua L. Journal of Essential Oil Research, 1, 201-202. https://doi.org/10.1080/10412905.1989.9697786Council of Europe (1997) European Pharmacopoeia. 3rd Edition, Council of Europe, Strasbourg.König, W.A., Joulain, D. and Hochmuth, D.H. (2004) Terpenoids and Related Constituents of Essential Oils. Library of MassFinder, 2.Adams, R.P. (2007) Identification of Essential Oil Components by Gas Chromatography/Mass Spectrometry. Allured Publishing Corporation, Carol Stream.NIST (National Institute of Standards and Technology) (2016) NIST/EPA/NIH Mass Spectral Library with Search Program. http://www.nist.gov/srd/nist1a.cfmSoylu, E.M., Yiğitbaş, H., Tok, F.M., Soylu, S., Kurt, Ş., Baysal, Ö. and Kaya, A.D. (2005) Chemical Composition and Antifungal Activity of the Essential oil of Artemisia annua L. against Foliar and Soil-Borne Fungal Pathogens. Journal of Plant Diseases and Protection, 112, 229-239. https://www.jstor.org/stable/45154906Endrias, A. (2006) Bio-raffinage de plantes aromatiques et médicinales appliqué à l’Hibiscus sabdariffa L. et à l’Artemisia annua. Ph.D. Thesis, Institut National Polytechnique de Toulouse, Toulouse.Möllenbeck, S., König, T., Schreier, P., Schwab, W., Rajaonarivony, J. and Ranarivelo, L. (1997) Chemical Composition and Analyses of Enantiomers of Essential Oils from Madagascar. Flavour and Fragrance Journal, 12, 63-69. https://doi.org/10.1002/(SICI)1099-1026(199703)12:2<63::AID-FFJ614>3.0.CO;2-ZBlanchard, J.M. (2007) Cinnamomum Camphora with Cineol (ravintsara): A Plant for the Prevention of Nosocomial Infections. Phytothérapie, 5, 15-20. https://doi.org/10.1007/s10298-007-0202-1Ankita, S., Chandra, S.S. and Arti, T. (2013) Phytochemical Study and Antimicrobial Activities of Cinnamomum camphora. World Journal of Pharmaceutical research, 3, 2287-2294.Costa, R., Pizzimenti, F., Marotta, F., Dugo, P., Santi, L. and Mondello, L. (2010) Volatiles from Steam-Distilled Leaves of Some Plant Species from Madagascar and New Zealand and Evaluation of Their Biological Activity. Natural Product Communications, 5, 1803-1808. https://doi.org/10.1177/1934578X1000501123Malabadi, R.B., Kolkar, K.P., Meti, N.T. and Chalannavar, R.K. (2021) Traditional Herbal Folk Medicine Used for Controlling CORONA Virus (SARS-CoV-2) Disease (Covid-19). International Journal of Innovation Scientific Research and Review, 3, 1507-1517.(2021) Madagascar: La tisane “miracle” déclinée en gélulescontre le Covid-19.https://www.france24.com/fr/20201004-madagascar-la-tisane-miracle-d%C3%A9clin%C3%A9e-en-g%C3%A9lules-contre-le-Covid-19Ojah, E.O. (2020) Exploring Essential Oils as Prospective Therapy against the Ravaging Coronavirus (SARS-CoV-2). Iberoamerican Journal of Medicine, 2, 322-330. https://doi.org/10.53986/ibjm.2020.0056Patne, T., Mahore, J. and Tokmurke, P. (2020) Inhalation of Essential Oils: Could Be Adjuvant Therapeutic Strategy for Covid-19. International Journal of Pharmaceutical Sciences and Research, 11, 4095-4103. https://doi.org/10.13040/IJPSR.0975-8232.11(9).4095-03