Evaluation of phytochemicals, enzyme inhibitory, antibacterial and antioxidant effects of Psydrax dicoccos Gaertn.

The study was aimed to investigate the phytochemical composition, antioxidant, antibacterial and enzyme inhibitory effects of Psydrax dicoccos leaf (PDL). Hydroalcoholic extract (HAE) was recorded with high concentration of total phenolics (59.68 ± 0.3 mg GAE/g), total flavonoids (57.85 ± 0.5 mgQRE/g) and proanthocyanidin (24.98 ± 0.17 mgAAE/g). Ethyl acetate (31.76 ± 1.52 mgQE/g), methanolic (34.99 ± 0.16 mgAAE/g) and aqueous (75.00 ± 0.30 mgGAE/g) extracts showed a high amount of total flavanols, vitamin E and total tannins, respectively. GC-MS analysis facilitated the identification of 56 metabolites with squalene and cinnamic acid as prominent compounds. HAE showed moderate α-amylase (IC50 of 48.94 ± 0.5 µg/mL) and α-glucosidase (IC50 of 46.98 ± 0.5 µg/mL) inhibitory activities. HAE is also perceived as a potent radical scavenger, reducing agent, metal chelating power, and total antioxidant capacity. For antibacterial activity, the aqueous extract was most effective with the MIC ranged from 87.5 to 175 µg/mL. Further characterization and in vivo studies are suggested to validate its traditional claim as a potential source of therapeutic agents.

Therapeutic potential of phytoconstituents of edible fruits in combating emerging viral infections.

Plant-derived bioactive molecules display potential antiviral activity against various viral targets including mode of viral entry and its replication in host cells. Considering the challenges and search for antiviral agents, this review provides substantiated data on chemical constituents of edible fruits with promising antiviral activity. The bioactive constituents like naringenin, mangiferin, α-mangostin, geraniin, punicalagin, and lectins of edible fruits exhibit antiviral effect by inhibiting viral replication against IFV, DENV, polio, CHIKV, Zika, HIV, HSV, HBV, HCV, and SARS-CoV. The significance of edible fruit phytochemicals to block the virulence of various deadly viruses through their inhibitory action against the entry and replication of viral genetic makeup and proteins are discussed. In view of the antiviral property of active constituents of edible fruits which can strengthen the immune system and reduce oxidative stress, they are suggested to be diet supplements to combat various viral diseases including COVID-19. PRACTICAL APPLICATIONS: Considering the increasing threat of COVID-19, it is suggested to examine the therapeutic efficacy of existing antiviral molecules of edible fruits which may provide prophylactic and adjuvant therapy with their potential antioxidant, anti-inflammatory, and immune-modulatory effects. Several active molecules like geraniin, naringenin, (2R,4R)-1,2,4-trihydroxyheptadec-16-one, betacyanins, mangiferin, punicalagin, isomangiferin, procyanidin B2, quercetin, marmelide, jacalin lectin, banana lectin, and α-mangostin isolated from various edible fruits have showed promising antiviral properties against different pathogenic viruses. Especially flavonoid compounds extracted from edible fruits possess potential antiviral activity against a wide array of viruses like HIV-1, HSV-1 and 2, HCV, INF, dengue, yellow fever, NSV, and Zika virus infection. Hence taking such fruits or edible fruits and their constituents/compounds as dietary supplements could deliver adequate plasma levels in the body to optimize the cell and tissue levels and could lead to possible benefits for the preventive measures for this pandemic COVID-19 situation.

Comparative spasmolytic effect between Cinnamomum tamala and Cinnamomum verum leaf essential oils and eugenol through in vitro and in silico approaches.

Cinnamomum tamala and Cinnamomum verum are known for their folk medicinal usage in treating gastrointestinal ailments. The spasmolytic activity of essential oils was studied using isolated rat ileum. The results indicate that C. tamala, despite having a lower content of eugenol (60%), shows a spasmolytic potential of 68.01 ± 2.63% (EC50 = 110.12 ± 13.58 µg/mL) while C. verum with rich eugenol (80%) shows lesser spasmolytic potential (38.96 ± 0.63%) and fails to attain an EC50 value. Upon comparison with standard eugenol's percentage of spasmolytic (35.68 ± 2.57%), it is evident that the action of these essential oils does not solely rely on the major component but the synergistic role in association with other components of the mixture influences the pharmacological action of the essential oils. In silico docking of phytochemicals of leaf essential oils with M2 (M2AChR) and M3 muscarinic (M3AChR) and nicotinic acetylcholine receptor (nAChR) was carried out to determine the type of receptors through which the essential oils had spasmolytic potential. The binding affinity for eugenol with nAChR shows a better docking score than M2AChR and M3AChR.

Vasorelaxant property of Plectranthus vettiveroides root essential oil and its possible mechanism.

ETHNOPHARMACOLOGICAL RELEVANCE: Plectranthus vettiveroides (Jacob) N.P. Singh & B.D. Sharma is a traditional medicinal plant used in Siddha System of Medicine and its aromatic root is used to reduce the elevated blood pressure. AIM: The aim of the present study was to study vasorelaxant property of the root essential oil nanoemulsion (EON) of P. vettiveroides. METHODS: The EON was formulated to enhance the solubility and bioavailability and characterized. The preliminary screening was performed by treating the EON with aortic rings pre-contracted with phenylephrine (1 µM) and potassium chloride (80 mM). The role of K⁺ channels in EON induced vasorelaxation was investigated by pre-incubating the aortic rings with different K⁺ channel inhibitors namely, glibenclamide (a non-specific ATP sensitive K⁺ channel blocker, 10 µM), TEA (a Ca2⁺ activated non-selective K⁺ channel blocker, 10-2 M), 4-AP (a voltage-activated K⁺ channel blocker, 10-3 M) and barium chloride (inward rectifier K⁺ channel blocker, 1 mM). The involvement of extracellular Ca2+ was performed by adding cumulative dose of extracellular calcium in the presence and absence of EON and the concentration-response curve (CRC) obtained is compared. Similarly, the role of nitric oxide synthase, muscarinic and prostacyclin receptors on EON induced vasorelaxation were evaluated by pre-incubating the aortic rings with their inhibitors and the CRC obtained in the presence and absence of inhibitor were compared. RESULTS: The GC-MS and GC-FID analyses of the root essential oil revealed the presence of 62 volatile compounds. The EON exhibited significant vasorelaxant effect through nitric oxide-mediated pathway, G-protein coupled muscarinic (M3) receptor pathway, involvement of K+ channels (KATP, KIR, KCa), and blocking of the calcium influx by receptor-operated calcium channel. CONCLUSION: It is concluded that the root essential oil of P. vettiveroides is possessing marked vasorelaxant property. The multiple mechanisms of action of the essential oil of P. vettiveroides make it a potential source of antihypertensive drug.

Chemical characterization, antioxidant, antibacterial and enzyme inhibitory properties of Canthium coromandelicum, a valuable source for bioactive compounds.

The present study aimed at chemical characterization of Canthium coromandelicum leaf extracts (CCLE) and their in vitro pharmacological (antioxidant, enzyme inhibitory, and antibacterial) activities. Chemical characterization includes chemical profile of six extracts of CC by Gas chromatography - Mass spectrometry (GC-MS) analysis and total phenolics and flavonoids by spectrophotometric methods. Antioxidant activity was determined using eight assays. Enzymatic inhibitory property was evaluated by α-amylase and α-glucosidase inhibitory assays and antibacterial activity was studied against 10 pathogenic bacteria by agar disc diffusion method. GC-MS analysis enabled the identification of 65 compounds with palmitic acid, n-pentacosane, cycloartenol, linoleic acid, squalene, γ-sitosterol, nonacosane and α-tocopherol as major constituents of CCLE. Highest amount of total phenolics (58.03 mg GAE/g extract) and flavonoids (44.40 QE/g) was present in hydroalcoholic extract. Hydroalcoholic, methanolic and aqueous extracts showed significant free radical scavenging abilities and positive correlation was detected between antioxidant assays with recorded phenolics and flavonoids. Hydroalcoholic and methanolic extracts exhibited significant α-amylase (IC50 of 44.25 µg/mL) and α-glucosidase inhibitory activities (IC50 of 30.82 µg/mL) respectively.Methanolic and hydroalcoholic extracts at 750 µg/mL showed maximum antibacterial activity against S. typhi and S. flexneri respectively. Also, significant correlation was found between V. cholerae and R. equi as well as V. cholerae and S. epidermis. To conclude, C. coromandelicum could be considered as a natural antioxidant and potential source for therapeutic applications. However, widespread study is necessary to screen the role of recorded phytochemicals through in vivo studies to support its use in traditional medicine.

Root essential oil of Chrysopogon zizanioides relaxes rat isolated thoracic aorta - an ex vivo approach.

Root of Chrysopogon zizanioides (L.) Roberty has been used in Siddha system of medicine to treat hypertension. The present study was therefore to investigate the vasorelaxation effect of root essential oil of C. zizanioides using rat isolated thoracic aortic rings. Chemical characterization of root essential oil was carried out using Gas Chromatography-Flame Ionization Detector (GC-FID) and Gas Chromatography-Mass Spectrometry (GC-MS). Essential oil nanoemulsion (EONE) was prepared and characterized. Vasorelaxant effect of EONE in endothelium-intact aortic rings precontracted with phenylephrine (PE) (1 µM) or KCl (80 mM) was investigated. Role of Ca2+, nitric oxide and K+ channels in precontracted aortic rings were investigated to elucidate the mechanism of action of the essential oil. Further, the role of muscarinic and prostacyclin receptors in EONE induced relaxation was studied. The EONE significantly induced relaxation (Emax 77.1 ± 4.87%) in PE precontracted aortic rings. The nitric oxide synthase, and cyclooxygenase inhibitors and potassium channel blockers have not significantly inhibited the vasorelaxation induced by EONE. However, EONE induced relaxation in precontracted endothelium-intact aortic rings was significantly inhibited by muscarinic receptor and calcium channel. The root essential oil of C. zizanioides possesses vasorelaxant effect through muscarinic pathway as well as acts as calcium channel blocker.

Evaluation of chemical composition, antioxidant and anti-hyperglycemic activities of the essential oil based nanoemulsions of Cinnamomum litseifolium.

In the present study, antioxidant and anti-hyperglycemic activities of nanoemulsions of the leaf essential oils of Cinnamomum litseifolium Thwaites collected from two different locations in the Western Ghats namely, Kannikatty, Kalakad Mundandurai Tiger Reserve, Tamil Nadu (Cl1) and Karamanayar, Agasthyamalai hills, Kerala (Cl2), India were studied. Essential oils were extracted from the leaves and characterized by GC-FID and GC-MS. Slight variation in the composition of leaf essential oils was observed. Essential oil based nanoemulsions were prepared using a surfactant (Tween-80), co-surfactant (propylene glycol) and an emulsifier (lecithin) by homogenization followed by ultra-sonication. Upon characterization, the nanoemulsion of Cl1 showed better stability than Cl2. Both nanoemulsions inhibited α-amylase and α-glucosidase enzymes with IC50 values of 1.998 and 0.780 mg/mL for Cl1 and 3.587 and 1.455 mg/mL for Cl2 respectively.

Essential oils from unexplored aromatic plants quench biofilm formation and virulence of Methicillin resistant Staphylococcus aureus.

In the current study we have evaluated the antibiofilm and antivirulent properties of unexplored essential oils (EOs) obtained from Pogostemon heyneanus and Cinnamomum tamala against Methicillin Resistant Staphylococcus aureus (MRSA) strains. The EOs from both the aromatic plants was screened for their ability to prevent biofilm formation and to disrupt preformed biofilms. The efficacy of both the EOs to disrupt the preformed biofilms of various MRSA strains was determined by Confocal Laser Scanning Microscopy (CLSM) and Scanning Electron Microscopy (SEM).The EOs were further able to reduce the Extracellular polymeric substance (EPS) and slime synthesis the two factors of the biofilm assemblage. The EOs was also found to be effective in reducing virulence factors like staphyloxanthin and hemolysin. In silico docking studies were performed for the major components of essential oils and dehydroxysqualene synthase of MRSA which is responsible for the synthesis of staphyloxanthin. The results suggest that (E)-nerolidol showed better binding affinity towards the enzyme. Other compounds have similar binding strengths with the enzyme. Furthermore, the synergistic effect EOs along with the commercially available DNaseI and Marine Bacterial DNase (MBD) showed that the synergistic effect had enhanced biofilm disruption ability. The results show that EOs from P. heyneanus and C. tamala has potential antivirulent and biofilm inhibitory properties against clinical and drug resistant S. aureus strains. The present study highlights the importance of bioprospecting plant based natural products as an alternative for antibiotics owing to the emergence of multi-drug resistant strains.

Cumin scented leaf essential oil of Cinnamomum chemungianum: compositions and their in vitro antioxidant, α-amylase, α-glucosidase and lipase inhibitory activities.

As part of our work on prospecting of Cinnamomum of the Western Ghats, chemical compositions, antioxidant, α-amylase, α-glucosidase and lipase inhibitory activities of leaf essential oil (EO) of Cinnamomum chemungianum were evaluated. Chemical characterisation of the cumin scented leaf EO from five locations in the southern Western Ghats revealed that they were highly varied. EO from Kannikatti (CC2) exhibited good α-amylase inhibitory activity with IC50 value of 5.97 µg/mL, whereas the EOs from Chemungi (CC1) and Athirumala (CC5) showed better α-glucosidase inhibition with IC50 of 56.65 and 62.12 µg/mL, respectively. The EOs from Chemungi, Kannikatti and Athirumala were found to inhibit lipase with IC50 of 919.75, 923.17 and 838.46 µg/mL, respectively. The EO of C. chemungianum may be used in food products as it has cumin scent and mild inhibitory activities.

Antivirulent Properties of Underexplored Cinnamomum tamala Essential Oil and Its Synergistic Effects with DNase against Pseudomonas aeruginosa Biofilms - An In Vitro Study.

Pseudomonas aeruginosa is a nosocomial pathogen colonizing patients with chronic infectious diseases and has gained resistance to all the known broad spectrum antibiotics available today. The present study showcases the antibiofilm potential of an essential oil (EO) from an underexplored Cinnamomum species namely, C. tamala, against P. aeruginosa biofilms. Furthermore, the synergistic effects of the EO along with a commercially available DNase (DNaseI) and a DNase (MBD) isolated from a marine bacterium were explored for its antibiofilm activity. The results showed that the synergized action has maximum efficacy in inhibiting young and preformed biofilms. The synergized effect of EO and DNaseI showed 70% inhibition against matured biofilms of P. aeruginosa. The EO from C. tamala also showed quorum sensing inhibitory potential as it could inhibit the swarming motility behavior of P. aeruginosa. The synergistic action of EO and DNases offers a novel alternate therapeutic strategy for combating P. aeruginosa biofilm associated infections.

Vasorelaxant and cardiovascular properties of the essential oil of Pogostemon elsholtzioides.

ETHNOBOTANICAL RELEVANCE: Pogostemon elsholtzioides Benth. (Lamiaceae) is an aromatic shrub, endemic to eastern Himalaya region. The leaves are used for treating goiter and high blood pressure (BP) by indigenous people in Arunachal Pradesh, India. Young leaves are used as vegetable and leaf decoction is also used for cough, cold and headache by some indigenous communities in Northeast India. AIM OF THE STUDY: This species is used for treating hypertension and the genus Pogostemon is rich in essential oil. Therefore, the present study was aimed at investigation of the chemical constituents, vasorelaxant and cardiovascular effects of the essential oil of P. elsholtzioides. MATERIALS AND METHODS: P. elsholtzioides was collected from Pasighat, Arunachal Pradesh, India and essential oil was extracted from shade dried leaves. Essential oil was analyzed by GC-FID and GC-MS and the volatile constituents were identified. Vasorelaxant and cardiovascular properties of the essential oil were studied against phenylephrine induced contraction in isolated endothelium intact aortic preparations and by measuring systolic and diastolic BP, mean arterial pressure (MAP) and heart rate (HR) after carotid artery cannulation in Wistar rats. RESULTS: The essential oil was rich in sesquiterpenes and curzerene, benzophenone, α-cadinol and germacrone were major constituents. The essential oil exhibited significant vasodilation effect in phenylephrine induced contracted aortic rings. Vasorelaxant effect of the essential oil was also observed both in the presence and absence of Nitro-L-arginine methyl ester against phenylephrine-contracted aortic rings. It also induced reduction of systolic and diastolic BP, MAP and HR. CONCLUSIONS: Essential oil of P. elsholtzioides exhibited significant vasorelaxant effect against endothelium intact aortic preparation mediated through nitric oxide dependent pathway and also reduced BP. However, further study is needed to screen the role of calcium ions in both intracellular and extracellular pathway.

Variation in volatile constituents of Cinnamomum keralaense, endemic to the Western Ghats, India.

Leaf essential oils (EOs) of Cinnamomum keralaense, an endemic species to Southern Western Ghats, India, were investigated. Leaves were collected from three distinct populations and hydro-distilled to obtain EOs, which were analysed by GC-FID and GC-MS. A total of 68 constituents was identified from three EOs. Wide variation was found in the composition of EOs. Ten major compounds were identified from three EOs, however, none of the compound was present in all three EOs as major constituent. High content of methyl eugenol (82.5%) in one of the EOs is significant as it could be evaluated for commercial utilization. This is the first report on the chemical compositions of leaf EOs of C. keralaense.

Characterization of the leaf essential oils of an endemic species Cinnamomum perrottetii from Western Ghats, India.

Essential oils from the leaf of Cinnamomum perrottetii Meissn. collected from three distinct populations in the southern Western Ghats, India were analysed by GC-FID and GC-MS. A total of 56 volatile constituents representing 92.2-96.3% of the oils were identified. Variations in the chemical constituents of the oils were found. Only three major components namely, α-pinene (5.1-6.6%), tau-cadinol (8.7-20.5%) and α-cadinol (7.3-13%) out of 10 were found in all three samples. To the best of our knowledge, this is the first report on the chemical compositions of leaf essential oil of C. perrottetii.

Pogostemon hirsutus oil, rich in abietane diterpenes.

Volatile oil extracted from the leaves of Pogostemon hirsutus Benth., a rare species from Anamalai hills of the Western Ghats of Tamil Nadu, India was analyzed by GC-FID and GC-MS. Fifty-four compounds amounting to 90.8% of the oil were identified. The oil was rich in monoterpenes and diterpenes. The major components of the oil were alpha-pinene (11.5%), sabinene (8.5%), beta-pinene (5.2%), abietatriene (16.3%), dehydroabietal (3.5%) and dehydroabietol (21.0%). Abietane diterpenes are reported for the first time in the genus Pogostemon of Lamiaceae with six abietanes representing 42.6% of the oil.

Composition of the essential oil of Pogostemon travancoricus var. travancoricus.

The essential oil of Pogostemon travancoricus Bedd. var. travancoricus collected from the Agasthyamalai region of Tamil Nadu, India was analyzed by GC and GC-MS. The major components of the oil were bicyclogermacrene (16.0%), cis-calamenene (6.3%), germacrene B (11.1%), spathulenol (7.6%), viridiflorol (5.8%), alpha-cadinol (4.2%) and pogostone (9.9%).

Development of ITS sequence based molecular marker to distinguish, Tribulus terrestris L. (Zygophyllaceae) from its adulterants.

Tribulus terrestris L. (Zygophyllaceae) is one of the highly traded raw drugs and also used as a stimulative food additive in Europe and USA. While, Ayurvedic Pharmacopoeia of India recognizes T. terrestris as Goksura, Tribulus lanuginosus and T. subramanyamii are also traded by the same name raising issues of quality control. The nuclear ribosomal RNA genes and ITS (internal transcribed spacer) sequence were used to develop species-specific DNA markers. The species-specific markers efficiently amplified 295bp for T. terrestris (TT1F and TT1R), 300bp for T. lanuginosus (TL1F and TL1R) and 214bp for T. subramanyamii (TS1F and TS1R). These DNA markers can be used to distinguish T. terrestris from its adulterants.

Volatile oil composition of Pogostemon heyneanus and comparison of its composition with patchouli oil.

The volatile oil of the leaves of Pogostemon heyneanus Benth. (Lamiaceae) was analyzed by GC and GC-MS. Twenty-six components representing 96.0% of the oil were identified. The major components of the oil were acetophenone (51.0%), beta-pinene (5.3%), (E)-nerolidol (5.4%), and patchouli alcohol (14.0%). Comparison of the compositions of the oils of P. heyneanus and P. cablin (Blanco) Benth. (Patchouli oil) showed wide variation between them. Though 13 sesquiterpenes and oxygenated sesquiterpenes were detected in both oils, their concentrations in the oils differed widely. Acetophenone, benzoyl acetone and (E)-nerolidol present in the oil of P. heyneanus were not detected in patchouli oil.