Chemical composition of Callistemon citrinus (Curtis) Skeels aerial part essential oil and its pharmacological applications, neurodegenerative inhibitory, and genotoxic efficiencies

Enhancing bioactivity of Callistemon citrinus (Curtis) essential oil through novel nanoemulsion formulation

The main focus of this study was to create a stable and efficient nanoemulsion (NE) using Callistemon citrinus essential oil (EO). Various factors affecting the NE's stability were optimized including oil %, Tween 80%, time of sonication, and its accelerated stability was examined. The research also considered the antibacterial, antifungal, and larvicidal effects of the optimized NE (B10). The optimum NE stood out for its stability, featuring a particle size of 33.15 ± 0.32 nm. Analysis via IR spectroscopy confirmed successful EO encapsulation in B10. The formulation remained stable for six months, with B10 showing significantly higher antibacterial and antifungal potency compared to the pure oil. When samples were subjected to tests against Fusarium oxysporum, B10 exhibited a MIC value of 62.5 mg/mL, whereas the pure oil showed a MIC value of 250 mg/mL. This indicates that the B10 formulation was 50 times more effective than the EO. In terms of antibacterial activity against Escherichia coli, the MIC value was 0.256 mg/mL for B10 and 4 mg/mL for the EO. Also, pure oil and B10 displayed larvicidal effects against Chilo suppressalis (Walker) larvae, with B10 eliminating 95.2% of larvae in 48 h. Overall, stable and optimum C. citrinus NE with its strong antimicrobial qualities, shows promise as an effective fungicide and insecticide.

Comparative Studies of Essential Oil Composition and Biological Activities of Callistemon citrinus from Western Himalaya

This work described a comprehensive study to estimate chemical constituents of essential oils (EOs) extracted from different parts of the Callistemon citrinus viz: fruits, leaves and aerial part. The EOs were characterized using physicochemical parameters, and GC-FID/MS. It was observed that among different parts, aerial part has the highest oil yield (0.90 %) followed by leaves and fruits. Further, seventeen compounds were characterized, and represented total amount (97.2-99.5 %) with domination of monoterpenes (12.5-34.6 %) and oxygenated monoterpenes hydrocarbon (61.8-86.8 %). α-pinene (11.8-24.7 %), α-phellandrene (1.2-3.0 %), p-cymene (3.3-3.9 %) and 1,8-cineole (58.3-85.1 %) were found as major compounds in C. citrinus samples. These major compounds are the quality chemical markers of C. citrinus oil. The findings revealed significant quantitative variations in EO composition of samples and were also clearly supported by multivariate statistical analysis. Moreover, EOs were evaluated for glucosidase and colon cancer cell lines inhibitory activities, which were found promising.

Exploring the therapeutic potential of Prinsepia utilis Royle seed oil: A comprehensive study on chemical composition, physicochemical properties, anti-inflammatory, and analgesic activities

ETHNOPHARMACOLOGICAL RELEVANCE

Prinsepiautilis (PU) Royle, native to the Himalayan region, is a deciduous thorny shrub with numerous traditional uses of its roots, leaves and seeds for treatment of conditions such as rheumatic pain, joint pain, arthritis, and inflammation.

AIM OF THE STUDY

Keeping in mind the growing demand of products of natural origin as alternate medicine, the present study was undertaken to scientifically validate for the first time the traditional claims of healing pain and inflammation by evaluating the fatty oil isolated from the seeds using established in vitro and in vivo models.

MATERIALS AND METHODS

PU Seeds were Soxhlet extracted using n-hexane and fatty oil was isolated. Chemical composition of the oil was established with the aid of Gas Chromatography-Flame Ionization Detection (GC-FID) and Gas Chromatography-Mass Spectrometry (GC-MS). The oil was then subjected to in vitro anti-inflammatory activity by following the established protocols of trypsin inhibitory and bovine serum albumin denaturation assays. The acute toxicity of the oil was also studied using OECD guidelines 423. The anti-inflammatory property of the oil was further evaluated using carrageenan-induced and formalin-induced edema in the rat paw. Moreover, hot plate latency and tail immersion assay were employed to evaluate analgesic activity of the oil. To establish the quality of the oil, various physicochemical properties were also studied.

RESULTS

GC-FID and GC-MS analysis of the oil revealed the presence of linoleic acid (59.06 ± 0.00%), oleic acid (28.11 ± 0.01%), palmitic acid (9.51 ± 0.01%) and stearic acid (3.32 ± 0.01%). In vitro trypsin inhibitory and bovine serum albumin denaturation assay revealed dose-dependent notable activity of the oil with IC50 value of 63.57 μg/mL and 518.14 μg/mL, respectively. The physico-chemical characterization demonstrated that the oil possesses a low acidity and a high oxidative stability index. The oil was found to be non-toxic and displayed effective anti-inflammatory activities with significant inhibition till 4 h in carrageenan-induced and formalin-induced rat paw edema at maximum tested dose of 200 mg/kg b.w. The oil also exhibited significant results in hot plate latency and tail immersion assay with positive effects showing up to 4 h after dose administration.

CONCLUSION

These findings, besides supporting the traditional claims, suggest that P. utilis seed oil has potential therapeutic applications as a natural anti-inflammatory and analgesic agent. Further studies are warranted to explore its mechanisms of action and potential use in pharmaceutical and nutraceutical industries.

Chemical composition, seasonal variation and antiaging activities of essential oil from Callistemon subulatus leaves growing in Egypt

Callistemon is an aromatic genus of flowering plants belonging to family Myrtaceae. The essential oils of C. subulatus leaves were collected in four seasons and analyzed using GC/MS. The oils demonstrated monoterpenes as the predominant class. Eucalyptol was the main component in all seasons; summer (66.87%), autumn (58.33%), winter (46.74%) and spring (44.63%), followed by α-pinene; spring (31.41%), winter (28.69%), summer (26.34%) and autumn (24.68%). Winter oil, the highest yield (0.53 mL/100g), was further investigated for its inhibitory activity against enzymes associated with ageing; elastase and acetylcholinesterase. It remarkably inhibited elastase and acetylcholinesterase with IC₅₀ values of 1.05 and 0.20 µg/ml, respectively. A molecular docking study was conducted for the major oil components on the active sites of target enzymes. Eucalyptol revealed the best binding affinity for both enzymes. C. subualtus oil could be used as supplement for management of ageing disorders like skin wrinkles and dementia.

Phytochemical profiling and neuroprotective activity of Callistemon subulatus leaves against cyclophosphamide-induced chemobrain

Cyclophosphamide (CPA) is a chemotherapeutic drug used for various types of cancers. However, patients receiving CPA for long periods suffer cognitive impairment associated with difficulties in learning, decreased concentration, and impaired memory. Chemotherapy-induced cognitive impairment, known as chemobrain, has been attributed to enhanced oxidative stress and inflammatory response. The current study aimed to identify the phytoconstituents of Callistemon subulatus extract (CSE) using HPLC-ESI/MS-MS analysis and evaluate its neuroprotective activity against CPA-induced chemobrain in rats. Fourteen compounds were identified following HPLC analysis including, five phlorglucinols, four flavonol glycosides, a triterpene, and a phenolic acid. Forty rats were divided into five groups treated for ten days as follows; group I (control group), group II received CPA (200 mg/kg, i.p.) on the 7th day, groups III and IV received CSE (200 and 400 mg/kg respectively, orally) for ten days and CPA (200 mg/kg, i.p.) on the 7th day, and group V received only CSE (400 mg/kg, orally) for ten days. The administration of CSE effectively ameliorated the deleterious effects of CPA on spatial and short-term memories, as evidenced by behavioral tests, Y-maze and passive avoidance. Such findings were further confirmed by histological examination. In addition, CSE counteracted the effect of CPA on hippocampal acetylcholinesterase (AChE) activity enhancing the level of acetylcholine. Owing to the CSE antioxidant properties, it hindered the CPA-induced redox imbalance, which is represented by decreased catalase and reduced glutathione levels, as well as enhanced lipid peroxidation. Therefore, CSE may be a promising natural candidate for protection against CPA-induced chemobrain in cancer patients.

In vitro and in vivo anti-inflammatory activity of Cupressus torulosa D.DON needles extract and its chemical characterization

ETHNOPHARMACOLOGICAL RELEVANCE

Cupressus torulosa (family Cupressaceae), widely distributed in the north western Himalayan region of India, is a coniferous aromatic tree with various traditional uses of its aerial parts. Its needles have been used for anti-inflammatory, anticonvulsant, antimicrobial, and wound-healing properties.

AIM OF THE STUDY

The study aimed at investigating the previously unknown anti-inflammatory activity of the hydromethanolic extract of the needles employing in vitro and in vivo assays and scientifically validate traditional claim of their use in treatment of inflammation. Chemical characterization of the extract with the aid of UPLCQTOFMS was also of interest.

MATERIALS AND METHODS

C. torulosa needles were first defatted with hexane and sequentially extracted with chloroform and 25% aqueous methanol (AM). Since the presence of phenolics (TPCs, 208.21 ± 0.95 mg GAE/g needles) and flavonoids (TFCs, 84.61 ± 1.21 mg QE/g needles) was observed in the AM extract only, it was chosen for biological and chemical examinations. Acute toxicity of the AM extract on female mice was evaluated following the OECD guideline 423. In vitro anti-inflammatory activity of the AM extract was examined using egg albumin denaturation assay while carrageenan-induced paw edema and formalin-induced paw edema models at doses of 100, 200 and 400 mg/kg po were used to determine the in vivo activity of the AM extract on Wistar rats of either sex. The components of the AM extract were analyzed by UPLC-QTOF-MS method using non-targeted metabolomics approach.

RESULTS

AM extract was found to be non-toxic at 2000 mg/kg b.w. with no signs of abnormal locomotion, seizures and writhing. The extract demonstrated promising in vitro anti-inflammatory activity (IC₅₀ 160.01 μg/mL) compared to standard diclofenac sodium (IC₅₀ 73.94 μg/mL) in egg albumin denaturation assay. In carrageenan-induced paw edema and formalin-induced paw edema tests the extract showed significant anti- inflammatory activity (57.28% and 51.04% inhibition of paw edema, respectively) at the dose of 400 mg/kg p.o. after 4 h in comparison to the standard diclofenac sodium which displayed 61.39% and 52.90% inhibition, respectively, at the dose of 10 mg/kg p.o. after 4 h in these models. A total of 63 chemical constituents, majority of them being phenolics, were found in the AM extract of the needles. Two compounds namely monotropein (iridoid glycoside), (±)12-HETE (eicosanoid) and fraxin (coumarin glycoside) were reported to have anti-inflammatory effect.

CONCLUSIONS

For the first time our study demonstrated that hydro-methanolic extract of C. torulosa needles exhibit anti-inflammatory activity thereby supporting their traditional use in the treatment of inflammatory disorders. UPLCQTOFMS assisted chemical profile of the extract was also unveiled.

Phytochemical Profile, Preliminary Toxicity, and Antioxidant Capacity of the Essential Oils of Myrciaria floribunda (H. West ex Willd.) O. Berg. and Myrcia sylvatica (G. Mey) DC. (Myrtaceae)

The essential oils (EOs) of Myrciaria floribunda (Mflo) and Myrcia sylvatica (Msyl) (Myrtaceae) were obtained by hydrodistillation. The analysis of volatile constituents was performed by GC/MS. Preliminary toxicity was assessed on Artemia salina Leach. The antioxidant capacity was measured by the ABTS•+ and DPPH• radical inhibitory activities. The results indicate that the Mflo EO had the highest yield (1.02%), and its chemical profile was characterized by high levels of hydrocarbon (65.83%) and oxygenated (25.74%) monoterpenes, especially 1,8-cineole (23.30%), terpinolene (22.23%) and α-phellandrene (22.19%). Regarding the Msyl EO, only hydrocarbon (51.60%) and oxygenated (46.52%) sesquiterpenes were identified in the sample, with (Z)-α-trans-bergamotene (24.57%), α-sinensal (13.44%), and (Z)-α-bisabolene (8.33%) at higher levels. The EO of Mflo exhibited moderate toxicity against A. salina (LC50 = 82.96 ± 5.20 µg.mL−1), while the EO of Msyl was classified as highly toxic (LC50 = 2.74 ± 0.50 µg.mL−1). In addition, relative to Trolox, the EOs of Mflo and Msyl showed significant inhibitory effects (p < 0.0001) against the DPPH• radical. This study contributes to the expansion of chemical and biological knowledge on the EOs of Myrtaceae species from the Amazon region.

Anethole rich Clausena heptaphylla (Roxb.) Wight & Arn., essential oil pharmacology and genotoxic efficiencies

Anethole, a widely used industrial flavoring agent is majorly sourced from anise and star anise. The present study is aimed to the in-depth pharmacological analysis i.e. anti-diabetic, skin whitening, neurodegenerative disorder inhibitory activities of anethole-rich Clausena heptaphylla leaf essential oil (ARCHEO) (88.59%) as revealed by the Gas Chromatography/Mass Spectrometry (GC/MS) analysis and further confirmed by proton nuclear magnetic resonance ¹H-NMR as well as to compare with standard compound anethole. ARCHEO (ABTS EC₅₀ 6.97 ± 0.004 µg/mL; Protease assay 4.51 ± 0.004 µg/mL) outperformed the standard compound anethole (ABTS EC₅₀ 9.48 ± 0.048 µg/mL; Protease assay EC₅₀ 22.64 ± 0.016 µg/mL) in antioxidant and anti-inflammatory experiments. ARCHEO was also shown to be more effective than the reference compound anethole in terms of anti-diabetic activity (EC₅₀ 22.35 ± 0.121 µg/mL), tyrosinase inhibitory activity (EC₅₀ 16.45 ± 0.012 µg/mL), and anti-cholinesterase activity (EC₅₀ 22.32 ± 0.016 µg/mL). However, ARCHEO exhibited lower antimicrobial activity towards all the tested microbes compared to standard compound anethole and as for the MIC, ARCHEO was effective only towards Salmonella typhimurium (60 µg/mL), Streptococcus mutans (20 µg/mL), and Aspergillus fumigatus (75 µg/mL). ARCHEO (11.11%) and anethole (12.33%) showed no genotoxic effect based on Allium cepa assay mitotic index value. Thus, ARCHEO could be a commercially viable and widely available cheaper source of anethole, which has buoyant demand in the field of food flavoring, fragrance, and pharmaceutical industries.

Pharmacological action and underlying molecular mechanism of Callistemon: A genus of promising medicinal herbs

INTRODUCTION

The genus Callistemon belongs to a group of medically significant plants which have found tremendous use in traditional medicine across the globe. They are reported for anti-cancer, neuroprotective, anti-inflammatory, antioxidant, anti-microbial, and many other significant medicinal attributes. However, the current use of this genus is limited mainly to ornamental and recreational purposes. Recent studies have reported several novel compounds like phloroglucinol derivatives, terpenes, phenolics, etc., from Callistemon spp., which have great medical significance. Further, there is a surge of recent studies reporting novel pharmacological properties of Callistemon. The number of review studies discussing the underlying molecular mechanism behind the pharmacological action of Callistemon is quite limited.

METHODS

The literature search for studies published from 1991 to 2021 using Google scholar and PubMed were selected. The review documented relevant literature focused on Callistemon spp exhibiting significant pharmacological effects.

RESULTS

This review deals with the pharmacological properties of Callistemon and the underlying molecular mechanism responsible for protective effect in several pathophysiological conditions. This study updated the current information regarding the medicinal importance of Callistemon spp. for research and the public community.

DISCUSSION AND CONCLUSIONS

The preliminary studies, interrogating pharmacological properties of Callistemon spp., hold great promise and demand further research to decipher the mode of action. More and more research are needed in this direction to explore the full potential of the genus Callistemon as a medicinal herb.