Pharmacological properties of agarwood tea derived from Aquilaria (Thymelaeaceae) leaves: An emerging contemporary herbal drink

Characteristics of Growth, Photosynthesis, C/N Ratio, and Antioxidant Capacity in the Seedling Stage of Aquilaria sinensis 'Qinan'

In this study, Aquilaria sinensis 'Qinan', a strain of A. sinensis that easily forms agarwood, was selected and propagated by grafting seedlings. Existing research has mainly focused on the characteristics of agarwood formation, but little attention has been paid to the growth characteristics of A. sinensis 'Qinan'. In this study, the growth rate, photosynthetic capacity, leaf size, carbon and nitrogen contents, and antioxidant capacity were evaluated during the early growth stage in A. sinensis 'Qinan' and A. sinensis grafted seedlings. Compared with A. sinensis, A. sinensis 'Qinan' exhibited higher net photosynthetic rate (9.2 μmol m-2 s-1 in A. sinensis 'Qinan' and 7.8 μmol m-2 s-1 in A. sinensis) in the mature leaf. There were higher contents of secondary metabolites such as flavonoids and phenols, with stronger antioxidant capacity in A. sinensis 'Qinan'. Larger leaf area (43.9 cm2 in A. sinensis and 30.1 cm2 in A. sinensis 'Qinan'), higher nitrogen content (24.9 mg kg-1 in A. sinensis and 23.7 mg kg-1 in A. sinensis 'Qinan') in young leaves, faster growth rate, and larger biomass were observed in A. sinensis. The results indicate that differences exist in nutrient distribution during the growth process of A. sinensis 'Qinan' and A. sinensis, with more substances being used to synthesize defensive secondary metabolites in A. sinensis 'Qinan'.

Natural α-glucosidase inhibitors from Aquilaria sinensis leaf-tea: Targeted bio-affinity screening, identification, and inhibition mechanism

Aquilaria sinensis leaves have long been consumed as a popular replacement tea for lowering postprandial blood glucose levels, but their specific functional components remain unclear. In this study, Aquilaria sinensis leaf-tea 70 % ethanol extract (ALTE) exhibited excellent anti-α-glucosidase activity (IC50 = 6.93 ± 1.91 μg/mL) and promoted glucose consumption ability in 3 T3-L1 preadipocyte cells. Subsequently phenolic compositions of ALTE were identified for the first time. After that, five potential α-glucosidase inhibitors (α-GIs) including cynaroside-3,5-diglucose, malvidin 3-glucose, epicatechin, epigallocatechin gallate, and dihydromyricetin in ALTE were screened using a targeted bio-affinity ultrafiltration-HPLC/MS method. Moreover, these five α-GIs all showed good anti-α-glucosidase effects and glucose consumption-promoting ability. Furthermore, the binding properties and inhibition mechanisms of five α-GIs to α-glucosidase were further analyzed via enzyme inhibition kinetics, molecular docking, and molecular dynamics simulation. This study confirms that Aquilaria sinensis leaf-tea is effective in preventing post-hyperglycemia in vitro models, suggesting potential for future research in human trials.

Phenolics-Rich Extract from Agarwood Leaf-Tea Alleviate Dextran Sulfate Sodium (DSS)-Induced Ulcerative Colitis Via Modulating Intestinal Barrier Function, Liver Inflammation, and Gut Microbiota

SCOPE

At present, the incidence rate of ulcerative colitis (UC) continues to increase, causing a global burden. In addition, therapeutic drugs have great side effects. According to modern pharmacology, agarwood leaves have anti-inflammatory, antibacterial, hypoglycemic, and lipid-lowering effects. Therefore, this experiment on DSS induced colitis treatment of polyphenolic substances in agarwood leaves is feasible and in line with the current hot topic of using natural substances instead of drugs for treatment.

METHODS AND RESULTS

ALP supplementation promotes the expression of tight junction proteins occludin and Zonula occludens protein 1 (ZO-1) on colonic tissues, repairs the intestinal barrier, and relieves further colonic tissue damage. Besides, ALP effectively inhibits the activation of nuclear factor kappa-B (NF-кB) signaling pathway and reduces the release of proinflammatory cytokines. Moreover, ALP reverses the alteration of gut microbiota in the colitic mice by increasing the abundances of Parabacteroides, Chlamydia, and Lachnospiraceae, and decreasing the abundances of Bacteroides and Phocaeicola. Furthermore, the correlation analysis suggested that ALP can attenuate DSS-induced UC, which is probably related to the alterations in the gut microbiota.

CONCLUSION

ALP can ameliorate DSS-induced UC by modulating gut microbiota, intestinal barrier function, and inflammatory responses.

Pharmacology and therapeutic potential of agarwood and agarwood tree leaves in periodontitis

The main bioactive components of agarwood, derived from Aquilaria sinensis, include sesquiterpenes, 2-(2-phenethyl) chromone derivatives, aromatic compounds, and fatty acids, which typically exert anti-inflammatory, antioxidant, immune-modulating, hypoglycemic, and antitumor pharmacological effects in the form of essential oils. Agarwood tree leaves, rich in flavonoids, 2-(2-phenethyl) chromone compounds, and flavonoid compounds, also exhibit significant anti-inflammatory, antioxidant, and immune-modulating effects. These properties are particularly relevant to the treatment of periodontitis, given that inflammatory responses, oxidative stress, and immune dysregulation are key pathological mechanisms of the disease, highlighting the substantial potential of agarwood and agarwood tree leaves in this therapeutic area. However, the low solubility and poor bioavailability of essential oils present challenges that necessitate the development of improved active formulations. In this review, we will introduce the bioactive components, extraction methods, pharmacological actions, and clinical applications of agarwood and agarwood tree leaves, analyzing its prospects for the treatment of periodontitis.

Insights into Aquilaria phylogenetics through comparative plastomic resources

The plastid is an essential organelle for its role in photosynthesis and energy production and its genomic information is always employed as important evolutionary markers to explore the relationship among species. Agarwood (Aquilaria), prized for its aromatic blend, finds extensive use in various cultures as incense and perfume. Despite its high economic importance, the phylogenetic status among Aquilaria based on plastomes remains ambiguous due to the lack of available plastomic resources. To bridge this knowledge gap, 22 Aquilaria plastomes were newly sequenced, similar variation patterns in this genus were determined, including a shared 16 bp extension of the rps19 gene and seven highly variable regions. The analysis highlighted the highest prevalence of the A/T motif among simple sequence repeats in these plastomes. Further phylogenetic analysis revealed Aquilaria's phylogenetic implications with an expanded dataset. This comprehensive plastomic resource not only enhances our understanding of Aquilaria evolution but also presents potential molecular markers for DNA barcoding.

Tandem mass spectrometry (MS/MS) molecular networking guided profiling of small molecules from Aquilaria sinensis (Lour.) Gilg leaves and their bioactivity evaluation

INTRODUCTION

Agarwood, a fragrant resinous wood mainly formed by Aquilaria spp., is used worldwide as a natural fragrance and traditional medicine. A large amount of Aquilaria sinensis (Lour.) Gilg leaves are underutilised during the process of the agarwood industry, and the development of A. sinensis leaves as tea has recently attracted more and more attention. However, the small molecule profile of A. sinensis leaves and their bioactivities has been rarely reported.

OBJECTIVE

To conduct a rapid untargeted liquid chromatography-mass spectrometry (LC-MS) analysis of A. sinensis leaves with a molecular networking (MN) strategy and evaluate its antioxidant and antidiabetic value.

METHOD

A MN-assisted tandem mass spectrometry (MS/MS) analysis strategy was used to investigate the small molecule profile of A. sinensis leaves. Additionally, the integration of antioxidant and α-glucosidase inhibitory assays with MN analysis was executed to expeditiously characterise the bioactive compounds for potential prospective application.

RESULTS

Five main chemical groups including phenol C-glycosides, organic acids, 2-(2-phenylethyl) chromones, benzophenone O-glycosides and flavonoids were rapidly revealed from the A. sinensis leaves. Eighty-one compounds were provisionally identified by comparing their MS/MS fragments with canonical pathways. The featured xanthone C-glycosides and benzophenone C-glycosides were recognised as the primary components of A. sinensis leaves. Several dimers and a trimer of mangiferin were reported firstly in A. sinensis leaves. Furthermore, 17 and 14 potential bioactive molecules were rapidly annotated from antioxidant and α-glucosidase inhibitory fraction, respectively.

CONCLUSION

Our findings will help expand the utilisation of A. sinensis leaves and thus promote the high-quality development of agarwood industry.

Aquilaria sinensis leaf tea affects the immune system and increases sleep in zebrafish

The importance of adequate sleep for good health cannot be overstated. Excessive light exposure at night disrupts sleep, therefore, it is important to find more healthy drinks that can promote sleep under sleep-disturbed conditions. The present study investigated the use of A. sinensis (Lour.) Spreng leaf tea, a natural product, to reduce the adverse effects of nighttime light on sleep. Here, Aquilaria sinensis leaf tea at 1.0 and 1.5 g/L significantly increased sleep time in zebrafish larvae (5-7 dpf) with light-induced sleep disturbance. Transcriptome sequencing and qRT-PCR analysis revealed a decrease in the immune-related genes, such as nfkbiab, tnfrsf1a, nfkbiaa, il1b, traf3, and cd40 in the 1.5 g/L Aquilaria sinensis leaf tea treatment group. In addition, a gene associated with sleep, bhlhe41, showed a significant decrease. Moreover, Aquilaria sinensis leaf tea suppressed the increase in neutrophils of Tg(mpo:GFP) zebrafish under sleep-disturbed conditions, indicating its ability to improve the immune response. Widely targeted metabolic profiling of the Aquilaria sinensis tea using ultra-performance liquid chromatography coupled with electrospray tandem mass spectrometry (UPLC-ESI-MS/MS) revealed flavonoids as the predominant component. Network pharmacological and molecular docking analyses suggested that the flavonoids quercetin and eupatilin in Aquilaria sinensis leaf tea improved the sleep of zebrafish by interacting with il1b and cd40 genes under light exposure at night. Therefore, the results of the study provide evidence supporting the notion that Aquilaria sinensis leaf tea has a positive impact on sleep patterns in zebrafish subjected to disrupted sleep due to nighttime light exposure. This suggests that the utilization of Aquilaria sinensis leaf tea as a potential therapeutic intervention for sleep disturbances induced by light may yield advantageous outcomes.

Feeding Aquilaria sinensis Leaves Modulates Lipid Metabolism and Improves the Meat Quality of Goats

Aquilaria (A.) sinensis is a medicinal plant widely grown in tropical South China. Given the abundant pruning waste of its leaves, the use of A. sinensis leaves is valuable. In this study, goats were fed a diet containing 20% A. sinensis leaves. Compared with the basal diet, feeding A. sinensis leaves to goats did not affect growth performance but considerably reduced the feeding cost. Strikingly, feeding A. sinensis leaves resulted in a significant decrease in the blood cholesterol levels (2.11 vs. 1.49 mmol/L, p = 0.01) along with a significant increase in the high-density lipoprotein levels (1.42 vs. 1.82 mmol/L, p = 0.01). There was also a tendency to lower the content of low-density lipoprotein levels in goats (0.78 vs. 0.45 mmol/L, p = 0.09). Furthermore, metabolomics analysis demonstrated that the reduction in cholesterol levels occurred in both the serum (0.387-fold change) and muscle (0.382-fold change) of goats during A. sinensis leaf feeding. The metabolic responses to feeding A. sinensis leaves suggest that the activation of lipolysis metabolism might happen in goats. These observed changes would be conducive to improving animal health and meat quality, ultimately benefiting human health.

Rediscovering the Therapeutic Potential of Agarwood in the Management of Chronic Inflammatory Diseases

The inflammatory response is a central aspect of the human immune system that acts as a defense mechanism to protect the body against infections and injuries. A dysregulated inflammatory response is a major health concern, as it can disrupt homeostasis and lead to a plethora of chronic inflammatory conditions. These chronic inflammatory diseases are one of the major causes of morbidity and mortality worldwide and the need for them to be managed in the long term has become a crucial task to alleviate symptoms and improve patients’ overall quality of life. Although various synthetic anti-inflammatory agents have been developed to date, these medications are associated with several adverse effects that have led to poor therapeutic outcomes. The hunt for novel alternatives to modulate underlying chronic inflammatory processes has unveiled nature to be a plentiful source. One such example is agarwood, which is a valuable resinous wood from the trees of Aquilaria spp. Agarwood has been widely utilized for medicinal purposes since ancient times due to its ability to relieve pain, asthmatic symptoms, and arrest vomiting. In terms of inflammation, the major constituent of agarwood, agarwood oil, has been shown to possess multiple bioactive compounds that can regulate molecular mechanisms of chronic inflammation, thereby producing a multitude of pharmacological functions for treating various inflammatory disorders. As such, agarwood oil presents great potential to be developed as a novel anti-inflammatory therapeutic to overcome the drawbacks of existing therapies and improve treatment outcomes. In this review, we have summarized the current literature on agarwood and its bioactive components and have highlighted the potential roles of agarwood oil in treating various chronic inflammatory diseases.

New Insights on Acanthus ebracteatus Vahl: UPLC-ESI-QTOF-MS Profile, Antioxidant, Antimicrobial and Anticancer Activities

This study investigated the antioxidant, antimicrobial, anticancer, and phytochemical profiling of extracts from the leaves and stem/root of Acanthus ebracteatus (AE). The total phenolic content (TPC), total flavonoid content (TFC), 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) radical-scavenging activity, 2, 2′-azino-Bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical-scavenging activity, metal chelating activities (MCA), ferric reducing antioxidant power (FRAP) and oxygen radical antioxidant capacity (ORAC) were used for antioxidant assessment. The ethanolic extracts of the leaves (AEL-nor) and stem/root (AEWP-nor) without chlorophyll removal and those with chlorophyll removal, using sedimentation process (AEL-sed and AEWP-sed), were prepared. Generally, AEL-sed showed the highest antioxidant activity (FRAP: 1113.2 µmol TE/g; ORAC: 11.52 µmol TE/g; MCA: 47.83 µmol EDTA/g; ABTS 67.73 µmol TE/g; DPPH 498.8 µmol TE/g; TPC: 140.50 mg/GAE g and TFC: 110.40 mg/CE g) compared with other extracts. Likewise, AEL-sed also showed the highest bacteriostatic (MIC) and bactericidal (MBC) effects, as well as the highest anticancer and antiproliferative activity against oral squamous carcinoma (CLS-354/WT) cells. UPLC-ESI-QTOF/MS analysis of AEL-sed and AEWP-sed tentatively identified several bioactive compounds in the extracts, including flavonoids, phenols, iridoids, and nucleosides. Our results provide a potentially valuable application for A. ebracteatus, especially in further exploration of the plant in oxidative stress-related disorders, as well as the application of the plant as potential nutraceuticals and cosmeceuticals.

Comparison of phenolic compounds contained in Aquilaria leaves of different species

Leaves of Aquilaria plants contain a variety of phenolic compounds such as iriflophenone glycosides, mangiferin, and genkwanin. Previous studies showed that Aquilaria leaf extracts exhibit many pharmacological activities, including antidiabetic and laxative effects. However, a few studies have reported differences in the chemical content and compositions of Aquilaria species. Here, three Aquilaria species were identified using matK and trnL-trnF sequences and their leaves were analyzed by HPLC and LC/MS. Comparison of the chemical components and α-glucosidase inhibition activity of the three species showed that the level of iriflophenone glycosides in A. rugosa was higher than in A. sinensis and A. crassna. There was no difference in the α-glucosidase inhibition activity of leaf extracts of the three species, but the strength of the inhibition activity can possibly be explained by the total sum of active compounds in the leaf extracts.

In Vitro Inhibitory Effects of Agarwood Tea (Aquilaria malaccensis Lamk) Aqueous Extract on Human Cytochrome P450 (CYP) Enzyme Activities

BACKGROUND

Agarwood tea derived from Aquilaria malaccensis Lamk is becoming an increasingly popular herbal drink that is said to have multiple health benefits. Co-administration of this tea and clinical used drugs is possible, but it increases the risk of drug-herb interactions.

OBJECTIVE

This in vitro study investigated the inhibitory effects of agarwood tea aqueous extract on the eight major human drug-metabolising cytochrome P450 (CYP) enzyme activities.

METHODS

High-throughput fluorescence-based Vivid® CYP450 screening kits were employed to obtain the enzyme activities before and after incubation with agarwood tea aqueous extract.

RESULTS

Agarwood aqueous extract potently inhibited CYP2C9, CYP2D6, and CYP3A4 activities with Ki values of 5.1, 34.5, and 20.3μg/ml, respectively. The most likely inhibition mode responsible for these inhibitions was non-competitive inhibition. On the other hand, at 1000μg/ml, agarwood tea aqueous extract negligibly inhibited CYP1A2, CYP2B6, CYP2C19, CYP2E1, and CYP3A5 activities.

CONCLUSION

These findings can be used to design additional in vitro investigations using clinical relevant drug substrates for CYP2C9, CYP2D6, and CYP3A4. Subsequently, future studies can be conducted to determine potential interactions between agarwood tea aqueous extract and CYP using in vivo models.

Fabrication and characterization of Agarwood extract-loaded nanocapsules and evaluation of their toxicity and anti-inflammatory activity on RAW 264.7 cells and in zebrafish embryos

Aquilaria malaccensis has been traditionally used to treat several medical disorders including inflammation. However, the traditional claims of this plant as an anti-inflammatory agent has not been substantially evaluated using modern scientific techniques. The main objective of this study was to evaluate the anti-inflammatory effect of Aquilaria malacensis leaf extract (ALEX-M) and potentiate its activity through nano-encapsulation. The extract-loaded nanocapsules were fabricated using water-in-oil-in-water (w/o/w) emulsion method and characterized via multiple techniques including DLS, TEM, FTIR, and TGA. The toxicity and the anti-inflammatory activity of ALEX-M and the extract-loaded nanocapsules (ALEX-M-PNCs) were evaluated in-vitro on RAW 264.7 macrophages and in-vivo on zebrafish embryos. The nanocapsules demonstrated spherical shape with mean particle diameter of 167.13 ± 1.24 nm, narrow size distribution (PDI = 0.29 ± 0.01), and high encapsulation efficiency (87.36 ± 1.81%). ALEX-M demonstrated high viability at high concentrations in RAW 264.7 cells and zebrafish embryos, however, ALEX-M-PNCs showed relatively higher cytotoxicity. Both free and nanoencapsulated extract expressed anti-inflammatory effects through significant reduction of the pro-inflammatory mediator nitric oxide (NO) production in LPS/IFNγ-stimulated RAW 264.7 macrophages and zebrafish embryos in a concentration-dependent manner. The findings highlight that ALEX-M can be recognized as a potential anti-inflammatory agent, and its anti-inflammatory activity can be potentiated by nano-encapsulation. Further studies are warranted toward investigation of the mechanistic and immunomodulatory roles of ALEX-M.

New Antiproliferative Triflavanone from Thymelaea hirsuta-Isolation, Structure Elucidation and Molecular Docking Studies

In this study isolates from Thymelaea hirsuta, a wild plant from the Sinai Peninsula of Egypt, were identified and their selective cytotoxicity levels were evaluated. Phytochemical examination of the ethyl acetate (EtOAc) fraction of the methanolic (MeOH) extract of the plant led to the isolation of a new triflavanone compound (1), in addition to the isolation of nine previously reported compounds. These included five dicoumarinyl ethers found in Thymelaea: daphnoretin methyl ether (2), rutamontine (3), neodaphnoretin (4), acetyldaphnoretin (5), and edgeworthin (6); two flavonoids: genkwanin (7) and trans-tiliroside (8); p-hydroxy benzoic acid (9) and β sitosterol glucoside (10). Eight of the isolated compounds were tested for in vitro cytotoxicity against Vero and HepG2 cell lines using a sulforhodamine-B (SRB) assay. Compounds 1, 2 and 5 exhibited remarkable cytotoxic activities against HepG2 cells, with IC₅₀ values of 8.6, 12.3 and 9.4 μM, respectively, yet these compounds exhibited non-toxic activities against the Vero cells. Additionally, compound 1 further exhibited promising cytotoxic activity against both MCF-7 and HCT-116 cells, with IC₅₀ values of 4.26 and 9.6 μM, respectively. Compound 1 significantly stimulated apoptotic breast cancer cell death, resulting in a 14.97-fold increase and arresting 40.57% of the cell population at the Pre-G1 stage of the cell cycle. Finally, its apoptosis-inducing activity was further validated through activation of BAX and caspase-9, and inhibition of BCL2 levels. In silico molecular docking experiments revealed a good binding mode profile of the isolates towards Ras activation/pathway mitogen-activated protein kinase (Ras/MAPK); a common molecular pathway in the development and progression of liver tumors.

Important Flavonoids and Their Role as a Therapeutic Agent

Flavonoids are phytochemical compounds present in many plants, fruits, vegetables, and leaves, with potential applications in medicinal chemistry. Flavonoids possess a number of medicinal benefits, including anticancer, antioxidant, anti-inflammatory, and antiviral properties. They also have neuroprotective and cardio-protective effects. These biological activities depend upon the type of flavonoid, its (possible) mode of action, and its bioavailability. These cost-effective medicinal components have significant biological activities, and their effectiveness has been proved for a variety of diseases. The most recent work is focused on their isolation, synthesis of their analogs, and their effects on human health using a variety of techniques and animal models. Thousands of flavonoids have been successfully isolated, and this number increases steadily. We have therefore made an effort to summarize the isolated flavonoids with useful activities in order to gain a better understanding of their effects on human health.

Thermal Degradation Kinetics and pH-Rate Profiles of Iriflophenone 3,5-C-β-d-diglucoside, Iriflophenone 3-C-β-d-Glucoside and Mangiferin in Aquilaria crassna Leaf Extract

The health benefits of the Aquilaria crassna Pierre ex Lecomte leaf extract (AE) make it very useful as an ingredient in food and pharmaceutical products. Iriflophenone 3,5-C-β-d-diglucoside (1), iriflophenone 3-C-β-d-glucoside (2) and mangiferin (3) are bioactive compounds of AE. We assessed the stability of AE by investigating the thermal degradation kinetics and shelf-life (t_90%) of compounds 1, 2 and 3 using Arrhenius plot models and studied their pH-rate profiles. The results demonstrate that 1 and 2 were degraded, following a first-order kinetic reaction. The degradation of 3 followed first-order reaction kinetics when present in a solution and second-order reaction kinetics in the dried powder form of the extract. According to the first-order kinetic model, the predicted shelf-life (t_90%) of the extract at 25 °C in dried form for compound 1 was 989 days with activation energy 129.86 kJ·mol⁻¹, and for 2 it was 248 days with activation energy 110.57 kJ·mol⁻¹, while in the extract solution, the predicted shelf-life of compounds 1–3 was 189, 13 and 75 days with activation energies 86.83, 51.49 and 65.28 kJ·mol⁻¹, respectively. In addition, the pH-rate profiles of 1–3 indicated that they were stable in neutral to acidic environments.

A feasible UHPLC-MS/MS method for concurrent quantification of 10 bioactive principles in Aquilaria leaf tea by the multiple reaction monitoring analytical mode

INTRODUCTION

Recently, the fresh leaves of Aquilaria trees have been processed as food products such as agarwood tea due to its beneficial medicinal properties. However, there have not been any reported analytical methods to quantify the bioactive principles in the processed products.

OBJECTIVE

A rapid and sensitive ultrahigh-performance liquid chromatography (UHPLC) coupled with electrospray ionisation (ESI) tandem mass spectrometry (MS/MS) method was developed and validated for the simultaneous determination of 10 bioactive components in Aquilaria leaf tea.

METHODS

The UHPLC-MS/MS was used for quantification operated in multiple reaction monitoring (MRM) mode. The optimised chromatographic parameters were conducted on a Shim-pack XR-ODS II column and mobile phases consisted of acetonitrile and 0.1% formic acid in water.

RESULTS

All the samples were analysed within 20 min. The established method showed excellent linearity (R² > 0.9988), good repeatability with all the relative standard deviation values lower than 3.27%, and satisfactory recovery (79.72-119.22%). The matrix effect factors ranged from 87.65 to 97.27% in the examination. The developed method was applied to the determination of 10 bioactive principles (1-10) in six different Aquilaria leaf tea samples. Among the analytes, mangiferin (1) and iriflophenone 2-O-α-l-rhamnopyranoside (2) were the most abundant compounds in the extracts of Aquilaria leaf tea, and it indicated that these biotech products may possess laxative effects.

CONCLUSION

This proposed method appeared to be a useful tool for the quality control of commercial products of Aquilaria leaf tea and thus provided an analytical reference for herbal drinks.

Metabolite Profiling of Aquilaria malaccensis Leaf Extract Using Liquid Chromatography-Q-TOF-Mass Spectrometry and Investigation of Its Potential Antilipoxygenase Activity In-Vitro

The Aquilaria malaccensis species of the genus Aquilaria is an abundant source of agarwood resin and many bioactive phytochemicals. Recent data regarding the chemical constituents and biological activities of Aquilaria leaves led us to attempt to qualitatively profile the metabolites of Aquilaria malaccensis leaves from a healthy, noninoculated tree through phytochemical screening, GC-MS, and LC/Q-TOF-MS. The present work is also the first to report the antilipoxygenase activity of A. malaccensis leaves from healthy noninoculated tree and investigate its toxicity on oral mucosal cells. A total of 53 compounds were tentatively identified in the extract, some of which have been described in literature as exhibiting anti-inflammatory activity. A number of compounds were identified for the first time in the extract of A. malaccensis leaf, including quercetin, quercetin-O-hexoside, kaempferol-O-dirhamnoside, isorhamnetin-O-hexoside, syringetin-O-hexoside, myricetin, tetrahydroxyflavanone, hesperetin, sissotrin, and lupeol. The antilipoxygenase assay was used to determine the lipoxygenase (LOX) inhibitory potential of the extract, while a WST-1 assay was conducted to investigate the effect of the extract on oral epithelial cells (OEC). The extract implied moderate anti-LOX activity with IC50 value of 71.6 µg/mL. Meanwhile, the cell viability of OEC ranged between 92.55% (10 µg/mL)–76.06% ± (100 µg/mL) upon treatment, indicating some potential toxicity risks. The results attained encourage future studies of the isolation of bioactive compounds from Aquilaria malaccensis leaves, as well as further investigation on the anti-inflammatory mechanisms and toxicity associated with their use.