Prakash Goswami

Chemical Composition and Allelopathic, Antibacterial, Antifungal, and Antiacetylcholinesterase Activity of Fish-mint (Houttuynia cordataThunb .) from India

Fish‐mint (Houttuynia cordataThunb.), belonging to family Saururaceae, has long been used as food and traditional herbal medicine. The present study was framed to assess the changes occurring in the essential‐oil composition of H. cordata during annual growth and to evaluate allelopathic, antibacterial, antifungal, and antiacetylcholinesterase activities. The essential‐oil content ranged from 0.06 – 0.14% and 0.08 – 0.16% in aerial parts and underground stem, respectively. The essential oils were analysed by GC‐FID, GC/MS, and NMR (1H and 13C). Major constituents of aerial‐parts oil was 2‐undecanone (19.4 – 56.3%), myrcene (2.6 – 44.3%), ethyl decanoate (0.0 – 10.6%), ethyl dodecanoate (1.1 – 8.6%), 2‐tridecanone (0.5 – 8.3%), and decanal (1.1 – 6.9%). However, major constituents of underground‐stem oil were 2‐undecanone (29.5 – 42.3%), myrcene (14.4 – 20.8%), sabinene (6.0 – 11.1%), 2‐tridecanone (1.8 – 10.5%), β‐pinene (5.3 – 10.0%), and ethyl dodecanoate (0.8 – 7.3%). Cluster analysis revealed that essential‐oil composition varied substantially due to the plant parts and season of collection. The oils exhibited significant allelopathic (inhibition: 77.8 – 88.8%; LD50: 2.45 – 3.05 μl/plate), antibacterial (MIC: 0.52 – 2.08 μl/ml; MBC: bacteriostatic) and antifungal (MIC: 2.08 – 33.33 μl/ml; MFC: 4.16 – 33.33 μl/ml) activities. The results indicate that the essential oil from H. cordata has a significant potential to allow future exploration and exploitation as a natural antimicrobial and allelopathic agent.

Essential oil composition of Peperomia pellucida (L.) Kunth from India

Hydrodistilled essential oil of Peperomia pellucida (L.) Kunth, collected from the foothills of Uttarakhand was analyzed using gas chromatography–flame ionization detection (GC–FID) and GC–mass spectrometry (GC–MS). A total of fifty constituents, representing 94.3–97.9% of the total oil composition, were identified. Major constituents of the oil of whole herb were carotol (26.6–32.0%), dill apiole (25.1–30.2%), pygmaein (5.5–10.5%), (E)-caryophyllene (5.6–8.3%), germacrene D (3.1–4.7%), β-elemene (3.0–4.2%), camphor (< 0.05–2.8%), daucene (0.8–2.7%), apiole (1.5–2.5%), β-bisabolene (0.2–2.2%) and bicyclogermacrene (1.6–2.1%). However, the root oil contained higher amount of apioles (dill apiole 63.9% and apiole 9.2%) compared with the aerial parts (dill apiole 20.7% and apiole 1.1%) of P. pellucida.

Chemical Constituents of Floral Volatiles of Plumeria rubra L. from India

The flower volatile constituents of Plumeria rubra L. grown in foothills of north India were analyzed by gas chromatography (GC) and GC-mass spectrometry (GC-MS). Altogether 31 constituents, representing 94.0% of flower essential oil and 89.2% of steam volatile extract were identified. Benzyl esters (49.0%, 41.4%), aliphatic alkanes (25.8%, 7.2%), oxygenated monoterpenes (0.1%, 27.1%), oxygenated sesquiterpenes (9.5%, 8.8%), and diterpene (9.4%, 0.2%), were the major class of constituents. Benzyl salicylate (26.7%, 33.5%), benzyl benzoate (22.3%, 7.9%), geraniol (trace, 17.2%), (E,E)-geranyl linalool (9.4%, 0.2%), tricosane (8.3%, 1.1%), linalool (0.1%, 8.0%), nonadecane (7.0%, 3.8%), (E)-nerolidol (7.0%, 5.5%), and pentacosane (4.4%, 0.3%) were the major constituents identified in flower oil and hydrodistilled volatile distillate. Results were compared with reported floral compositions of P. rubra that revealed considerate qualitative and quantitative variations. Alkanoic acids, neryl phenylacetate, phenylacetaldehyde, β-phenylethyl alcohol reported earlier were not present in P. rubra grown in India.

Chemical Composition and Antibacterial Activity of the Essential Oil of Kauri Pine [ Agathis robusta (C. Moore ex F. Muell.) F.M. Bailey] from India

Agathis robusta (C. Moore ex F. Muell.) F.M. Bailey, commonly known as Queensland Kauri or smooth-barked Kauri, is a coniferous tree in the family Araucariaceae. This study aimed to investigate the chemical composition and antibacterial activity of the essential oil of A. robusta from India. The hydrodistilled resin and leaf essential oils were analyzed using GC-FID and GC-MS. Altogether, 34 constituents (forming 98.2% of the resin oil) and 43 constituents (forming 91.2% of the leaf oil composition) were identified. Major constituents of the resin oil were isobornyl acetate (37.9%), limonene (12.3%), bornyl acetate (7.4%), and myrtenol (5.8%), while the leaf oil contained β-selinene (18.1%), rimuene (14.2%), caryophyllene oxide (11.5%), spathulenol (10.5%), α-selinene (9.8%), and γ-muurolene (5.8%) as main constituents. The resin essential oil showed minimum inhibitory concentration (MIC) in the range of 250–500 μg/mL and minimum bactericidal concentration (MBC) in the range of 500 to >1000 μg/mL against pathogenic strains of eight bacteria.

Composition and antibacterial activity of the essential oil of Artemisia nilagirica var. septentrionalis from India

Abstract Essential oil composition of the aerial parts of Artemisia nilagirica (Clarke) Pamp. var. septentrionalis Pamp. was analyzed by GC-FID and GC-MS methods. Altogether forty-one constituents were identified, accounting for 95.9% of total composition. The essential oil was characterized by monoterpenoids (76.6%) represented by artemisia ketone (62.6%), artemisia alcohol (3.7%), perillene (3.1%), bornyl acetate (1.4%), along with sesquiterpenoids (16.1%) viz. β-caryophyllene (3.5%), α-muurolol (3.5%), δ-cadinene (2.1%) and germacrene D (1.8%). Essential oil was tested against nine pathogenic bacterial strains viz. Staphylococcus aureus (MTCC 96), Staphylococcus aureus (MTCC 2940), Streptococcus mutans, Staphylococcus epidermidis, Bacillus subtilis, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhimurium. Based on zone of inhibition and MIC/MBC results, it is concluded that the essential oil of A. nilagirica var. septentrionalis exhibited good antibacterial activity against Staphylococcus aureus (MTCC-2940), Staphylococcus aureus (MTCC-96) and Bacillus subtilis, and moderate activity against Escherichia coli, Staphylococcus epidermidis, Salmonella typhimurium, and Streptococcus mutans.

Characterization of the Leaf Essential Oil Composition of Annonasquamosa L. from Foothills of North India

The leaf essential oil composition of Annona squamosa L., collected from the lower region of Himalaya was investigated using gas chromatography-flame ionisation detector (GC-FID) and GC-mass spectrometry (GC-MS). A total of forty-three constituents, representing 88.6% of the total oil composition were identified. The essential oil was primarily composed of sesquiterpenoids (sesquiterpene hydrocarbons: 63.4% and oxygenated sesquiterpenes: 21.8%). Major constituents of the oil were (E)-caryophyllene (15.9%), γ-cadinene (11.2%), epi-α-cadinol (9.4%), (Z)- caryophyllene (7.3%), γ-muurolene (5.4%), α-humulene (5.2%), viridiflorene (5.0%), α-cadinol (3.9%), aromadendrene (2.9%), δ-cadinene (2.9%), α-cadinene (2.9%), (2Z,6Z)-farnesal (2.2%) and caryophyllene oxide (2.1%).

Essential oil composition of Artemisia stelleriana Besser from India

Abstract Artemisia stelleriana Bess. (Asteraceae), commonly known as ‘dusty miller’ or ‘beach wormwood’, is a perennial shrub that is used traditionally as a carminative and in the treatment of peptic ulcer. In this study, the essential oil composition of fresh aerial parts of A. stelleriana from India was analyzed using gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Altogether, fifty-two constituents, forming 92.3% of the total oil compositions were identified, representing 49.5% of monoterpenoids and 42.8% of sesquiterpenoids. 1,8-Cineole (29.5%), germacrene D (5.6%), vulgarone B (3.1%), davanone B (3.0%), artedouglasia oxides (22.5%) viz., artedouglasia oxide A (8.0%), artedouglasia oxide C (5.5%), artedouglasia oxide D (5.0%) and artedouglasia oxide B (4.0%) were identified as the major constituents of the essential oil. This is the first report on essential oil composition of A. stelleriana from India.

Chemical Composition and Antibacterial Activity of Bidens pilosa

Bidens pilosa L., which belongs to the family Asteraceae, is an annual plant originating from South America and now found in almost all tropical and subtropical regions across the world [1]. In India, the freshly harvested leaves of B. pilosa are used in the preparation of ‘‘Ladakhi tea,’’ which is locally known as ‘‘Saja’’ or ‘‘Soljaa’’ in the cold desert of Ladakh Himalaya [2]. B. pilosa stands out among the species of the genus due to the presence of diverse phytomolecules and biological activities. The main compounds of the species are flavonoids and polyacetylenes [3, 4]. Besides its diverse medicinal uses, B. pilosa has been subjected to limited investigation in India [2]. This study focuses on the characterization of the root essential oil composition of B. pilosa from India and its antibacterial activity. Fresh roots of the B. pilosa collected from the lower region of Himalaya yielded 0.04 0.01% essential oil on hydrodistillation. The resulting essential oil was subjected to GC-FID (DB-5 capillary column, 30 m 0.25 mm i.d., film thickness 0.25 m; temperature; oven: 60–230 C, programmed at 3 C/min) and GC-MS (ionization energy 70 eV; mass scan range 40–450 amu) analyses. Altogether 50 constituents, representing 89.6 6.03% of the total oil composition, were identified (Table 1). The major constituents of the oil were octadecadienol (32.8 4.45%), bornyl acetate (19.4 3.11%), n-hexadecanol (7.7 0.60%), 7-phenylhept-2-en-4,6-diynyl acetate (3.2 2.53%), -pinene (2.8 1.66%), camphene (2.5 1.57%), -copaene (2.4 0.82%), cis-chrysanthenyl acetate (2.4 0.15%), eugenol isobutyrate (1.8 1.18%), octadecadienyl acetate (1.7 0.30%), and isoborneol (1.6 0.66%). This essential oil was evaluated against nine bacterial strains [four Gram-positive strains: Staphylococcus aureus (MTCC 2940), Staphylococcus aureus (MTCC 96), Streptococcus mutans (MTCC 890), Bacillus subtilis (MTCC 121), and five Gram-negative strains: Klebsiella pneumoniae (MTCC 109), Escherichia coli (MTCC 723), Escherichia coli (DH5 ), Pseudomonas aeruginosa (MTCC 741), and Salmonella typhimurium (MTCC 98)]. The oil exhibited moderate activity against Staphylococcus aureus (MTCC 2940) and Staphylococcus aureus (MTCC 96) with net zones of inhibition of 7.0 mm and 5.0 mm, respectively. This oil showed low activity against Streptococcus mutans (MTCC 890) with a net zone of inhibition of 3.0 mm. However, the oil exhibited no activity against Gram-negative strains. In earlier studies, different compositions were reported from different places for B. pilosa root oil. 1-Phenylhepta-1,3-diyn-5-en-7-ol acetate was identified as the major component of root essential oil of B. pilosa [5]. However, bornyl acetate (24.1%), octadecadienol (23.8%), 7-phenylhept-2-en-4,6-diynyl acetate (22.5%), and n-hexadecanol (7.1%) were reported as the main constituents of B. pilosa root essential oil [6].

Chemical composition and antibacterial activity of p-menthane chemotype of Cymbopogon martini (Roxb.) W. Watson (Poaceae) from India

Abstract In this study, the essential oil composition and antibacterial activity of an underexplored population of Cymbopogon martinii (Roxb.) W. Watson was investigated using GC–FID, GC–MS, disc diffusion and micro dilution broth assay. To substantiate the stability of the essential oil profile, the population was grown in the experimental field and its oil was analysed at different growth stages. Altogether, forty-eight constituents, comprising 91.5–96.8% of the total oil composition were identified. Main constituents of the oil were trans-p-mentha-2,8-dien-1-ol (16.6–22.8%), cis-p-mentha-2,8-dien-1-ol (7.2–9.7%), trans-p-mentha-1(7),8-dien-2-ol (9.8–15.8%), cis-p-mentha-1(7),8-dien-2-ol (11.3–18.0%), limonene (10.5–34.8%), isopiperitenol (3.1–5.0%), trans-carveol (3.5–4.5%) and carvone (2.6–3.6%). The oil exhibited wide spectrum, moderate to very good activity against pathogenic bacterial strains (zone of growth inhibition: 9–25 mm; minimum inhibitory concentration, MIC: 125–500 μg/mL). In conclusion, due to high percentage of monoterpene alcohols, the examined oil demonstrated potent antibacterial activity against both Gram-positive and Gram-negative strains.

p-Menthenols chemotype of Cymbopogon distans from India: composition, antibacterial and antifungal activity of the essential oil against pathogens

Abstract Cymbopogon distans (Nees. ex. Steud.) W. Watson (family: Poaceae) is a perennial aromatic grass widely distributed in tropical and subtropical zones of north-western Himalaya. The essential oil of C. distans has industrial potential for aromatherapy, fragrances and for natural aroma isolates. In view of chemotypic variations and industrial potential of the essential oil of C. distans, the present study was carried out to investigate the variability in chemical composition of p-menthenols chemotype of the C. distans harvested in different seasons during annual growth, and to evaluate the antimicrobial potential of its essential oil against pathogenic bacterial and fungal strains. The major constituents identified in essential oil of C. distans were cis-p-menth-2-en-1-ol (24.5–26.7%), δ-2-carene (19.9–28.2%), cis-piperitol (10.9–23.6%), trans-p-menth-2-en-1-ol (8.4–13.3%) and trans-piperitol (5.4–7.3%). The essential oil showed antagonist activity against nine bacterial strains (MIC: 250–1000 μg/mL) and three fungal strains (MIC: 130–530 μg/mL). Results revealed that the essential oil of C. distans possessed >50.0% of p-menthenols viz., cis-p-menth-2-en-1-ol, trans-p-menth-2-en-1-ol, cis-piperitol and trans-piperitol as major constituents, with a significant antimicrobial potential for pathogenic microbial strains.