Phytochemical Study of Aerial Parts of Leea asiatica

Therapeutic potential of Leea asiatica: Chemical isolation and validation of ethnomedicinal claims through in vitro and in silico assessment of antioxidant and anti-inflammatory properties

Leea asiatica (L.) Ridsdale has been used by different ethnic communities to manage diseased conditions that can be traced to oxidative stress and cellular inflammations but scientific evidences to support the claim are scanty. The objective of this study was to isolate and identify the antioxidants present in the aerial parts of Leea asiatica, perform their molecular docking against proteins to inspect whether the traditional uses of the plant can be validated by an in-silico approach. Quercetin (1), gallic acid (2), kaempferol (3), methyl gallate (4), myricetin 3-O-α-L-rhamnopyranoside (5), (-)-epicatechin-3-O-gallate (6) and (-)-epigallocatechin-3-O-gallate (7) were isolated from the 70 % methanolic extract of the aerial parts. Compounds 2, 4, 6, and 7 are reported for the first time from Leea asiatica. Quercetin (1), gallic acid (2), (-)-epicatechin-3-O-gallate (6) and (-)-epigallocatechin-3-O-gallate (7) showed potent antioxidant activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. Molecular docking with NADPH oxidase and TNF-α revealed that epicatechin-3-O-gallate, epigallocatechin-3-O-gallate and quercetin bound with the least binding energy amongst the isolated compounds as well as standard (Trolox and Prednisolone). By molecular dynamics analysis, epicatechin-3-O-gallate maintained stable conformation with NADPH oxidase and TNF-α and was found to possess good ADMET profile thereby validating the ethnic use of the plant as a medicine in the management of inflammatory conditions by an in vitro and in silico approach.

Seven new triterpenoids from the roots of Adenophora tetraphylla (Thub.) Fisch

Seven new triterpenoids, named Adeterpenoids A-G (1-7) and eight known compounds (8-15), were isolated from 70% ethanol extract of the roots of Adenophora tetraphylla (Thub.) Fisch. The compounds from it were separated by column chromatography techniques such as silica gel, ODS, and preparative liquid chromatography. Their structures were clarified based on extensive spectral analysis (1D, 2D-NMR, HR-ESI-MS, IR, UV, and CD) and comparison with the literature. At the same time, all compounds were evaluated for their cytotoxic activity against the LN229 (human glioma cell line). The results showed that compounds 2, 5, 6, 13, and 14 had a significant inhibitory effect on LN229 cells.

Three new triterpenoids from the fruit of Eleutherococcus senticosus (Rupr.) Harms

A phytochemical investigation on the 70% EtOH extract of the fruit of Acanthpanax senticosus resulted in the isolation of three new triterpenoids, Falcatane C (1), Acasentrioid F (2), Acasentrioid G (3) together with twenty-seven known ones (4-30). Structural elucidation of all the compounds was performed by spectral methods such as 1D or 2D (1H-1H COSY, HSQC, and HMBC), NMR spectroscopy, and high-resolution mass spectrometry. Moreover, all compounds were evaluated for their effects on H2O2-induced neurotoxicity in human neuroblastoma SH-SY5Ycells. Compounds 13 and 15 showed significant neuroprotective impact at a specific concentration, and compounds 1, 3, 5, 9, 11, 13-15, 17, 20-21, 23-25, 27, 29-30 showed moderate neuroprotective effect. The current study suggests that triterpenes in Eleutherococcus senticosus (Rupr.) Harms may play an essential role in the neuroprotective properties.

Four Steroidal Saponins from the Trunks of Dracaena cambodiana with Inhibition of NO Production in LPS Activated RAW264.7 Cells

Dracaena cambodiana Pierre ex Gagnep. is well known as a medicinal plant and widely distributed in Vietnam. Phytochemical investigation on the trunks of D. cambodiana lead to the isolation of four undescribed compounds (1-4) together with seven known ones (5-11). Their structures were determined to be pennogenin-24-yl-O-β-D-glucopyranoside (1), 17α-hydroxycambodianoside C (2), (25R)-27-hydroxypenogenin 3-O-α-L-rhamnopyranosyl-(1→3)-[α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside (3), (3β,25R)-17α,22α-dihydroxy-furost-5-en-3-yl-O-α-L-rhamnopyranosyl-(1→3)-[α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside (4), dracagenin A (5), 1-O-β-D-glucopyranosyl-2-hydroxy-4-allylbenzene (6), 1-O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranosyl-2-hydroxy-allylbenzene (7), 2-O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranosyl-1-hydroxy-allylbenzene (8), cinnamrutinoside A (9), icariside D1 (10), and seco-isolariciresinol 9-O-β-glucopyranoside (11) by extensive spectroscopic investigation, HR-ESI-MS, 1D and 2D NMR spectra. The anti-inflammatory activity of the isolated compounds was evaluated on macrophages. Compounds 1-6 significantly inhibited nitric oxide production in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages. Among them, compound 1 showed the best inhibitory activity with an IC50 value of 8.90±0.56 μM.

Terpenoid compounds from the fruits of Solanum virginianum

Eleven compounds were isolated and identified from ethanolic extracts of Solanum virginianum fruits, including two new compounds (1-2) and nine known compounds (3-11). Their structures were determined to be melongenaterpene C15-O-β-D-glucopyranoside (1), (9Z)-3,7,11,15-tetramethyl -hexadeca-1,6,10-triene-3,5,14,15-tetraol-5-O-β-D-glucopyranoside (2), actini-dioionoside A (3), byzantionoside B (4), citroside A (5), 7Z-roseoside (6), matenoside A (7), megastigmane (8), dihydrophaseic acid 3'-O-β-D-glucopyranoside (9), taraxerol (10), and huzhangoside C (11). In this paper, NMR spectroscopy was used to study the structures of the compounds, comparing their data with those in the literature. In addition, the potential anti-inflammatory activity of the compounds was also evaluated using the RAW264.7 cell inflammation model induced by lipopolysaccharide (LPS). The terpenoids showed no significant anti-inflammatory activity.

Discovery of Four New Compounds from Macropanax membranifolius and Their Cytotoxic Activity

A phytochemical investigation of the methanolic extract of the Macropanax membranifolius C.B. Shang leaves led to the isolation of three new flavans, (2R,3R)-4'-O-methylcatechin 5-O-β-D-glucopyranoside (1), (2S,3S)-4'-O-methylcatechin 5-O-β-D-glucopyranoside (2), (2S,3R)-4'-O-methylcatechin 5-O-β-D-glucopyranoside (3), one new triterpene glycoside 3-O-β-D-xylopyranosyl-(1→6)-[β-D-xylopyranosyl-(1→2)]-β-D-glucopyranosyl-oleanolic acid 28-O-β-D-glucopyranoside (4), together with nine known compounds (5-13). Their chemical structures were elucidated based on HR-ESI-MS, NMR spectroscopic data. The absolute configurations of compounds 1-3 were established by electronic circular dichroism (ECD) spectra. At concentration of 20 μM, compounds 1-13 showed the percentages of dead cell in the range of 2.14 % to 33.61 % against KB, HepG2, HL60, P388, HT29, and MCF7 cancerous cell lines by SRB assay.

A Perspective on Missing Aspects in Ongoing Purification Research towards Melissa officinalis

Melissa officinalis L. is a medicinal plant used worldwide for ethno-medical purposes. Today, it is grown everywhere; while it is known to originate from Southern Europe, it is now found around the world, from North America to New Zealand. The biological properties of this medicinal plant are mainly related to its high content of phytochemical (bioactive) compounds, such as flavonoids, polyphenolic compounds, aldehydes, glycosides and terpenes, among many other groups of substances. Among the main biological activities associated with this plant are antimicrobial activity (against fungi and bacteria), and antispasmodic, antioxidant and insomnia properties. Today, this plant is still used by society (as a natural medicine) to alleviate many other illnesses and symptoms. Therefore, in this perspective, we provide an update on the phytochemical profiling analysis of this plant, as well as the relationships of specific biological and pharmacological effects of specific phytochemicals. Currently, among the organic solvents, ethanol reveals the highest effectiveness for the solvent extraction of precious components (mainly rosmarinic acid). Additionally, our attention is devoted to current developments in the extraction and fractionation of the phytochemicals of M. officinalis, highlighting the ongoing progress of the main strategies that the research community has employed. Finally, after analyzing the literature, we suggest potential perspectives in the field of sustainable extraction and purification of the phytochemical present in the plant. For instance, some research gaps concern the application of cavitation-assisted extraction processes, which can effectively enhance mass transfer while reducing the particle size of the extracted material in situ. Meanwhile, membrane-assisted processes could be useful in the fractionation and purification of obtained extracts. On the other hand, further studies should include the application of ionic liquids and deep eutectic solvents (DES), including DESs of natural origin (NADES) and hydrophobic DESs (hDES), as extraction or fractionating solvents, along with new possibilities for effective extraction related to DESs formed in situ, assisted by mechanical mixing (mechanochemistry-based approach).

Chemical constituents from the leaves of psidium guajava linn. and their chemotaxonomic significance

The phytochemical investigation on the leaves of Psidium guajava Linn. led to the isolation and identification of 18 compounds, including six guavinoside (1-6), four flavonoids (7-10), eight triterpenoids (11-17) and one lignans (18). All chemical structures were elucidated via NMR spectroscopic methods, and further supported by comparison with literature data. Compounds 12, 14, 16 and 18 was isolated from the Myrtaceae family for the first time. The chemotaxonomic significance of these compounds was also discussed based on their structure types, as well as compounds-genus/family network analysis. The results showed that there were close chemotaxonomic relationships among the Myrtaceae, Asteraceae, and Lamiaceae families. Guavinosides A-F could be considered as valuable chemotaxonomic markers of Myrtaceae family, while guavinosides C-F might serve as chemotaxonomic markers for distinguishing the P. guajava.

In Vitro and in Silico Analysis of Phytochemicals From Fallopia dentatoalata as Dual Functional Cholinesterase Inhibitors for the Treatment of Alzheimer’s Disease

Current studies have found that butyrylcholinesterase (BuChE) replaces the biological function of acetylcholinesterase (AChE) in the late stage of Alzheimer’s disease. Species in the genus of Fallopia, rich in polyphenols with diverse chemical structures and significant biological activities, are considered as an important resource for screening natural products to against AD. In this study, thirty-four compounds (1–34) were isolated from Fallopia dentatoalata (Fr. Schm.) Holub, and their inhibitory effects against AChE and BuChE were assessed. Compounds of the phenylpropanoid sucrose ester class emerged as the most promising members of the group, with 31–33 displaying moderate AChE inhibition (IC50 values ranging from 30.6 ± 4.7 to 56.0 ± 2.4 µM) and 30–34 showing potential inhibitory effects against BuChE (IC50 values ranging from 2.7 ± 1.7 to 17.1 ± 3.4 µM). Tacrine was used as a positive control (IC50: 126.7 ± 1.1 in AChE and 5.5 ± 1.7 nM in BuChE). Kinetic analysis highlighted compounds 31 and 32 as non-competitive inhibitors of AChE with Ki values of ∼30.0 and ∼34.4 µM, whilst 30–34 were revealed to competitively inhibit BuChE with Ki values ranging from ∼1.8 to ∼17.5 µM. Molecular binding studies demonstrated that 30–34 bound to the catalytic sites of BuChE with negative binding energies. The strong agreement between both in vitro and in silico studies highlights the phenylpropanoid sucrose esters 30–34 as promising candidates for use in future anti-cholinesterase therapeutics against Alzheimer’s disease.

Comprehensive Analysis of Eleutherococcus senticosus (Rupr. & Maxim.) Maxim. Leaves Based on UPLC-MS/MS: Separation and Rapid Qualitative and Quantitative Analysis

Eleutherococcus senticosus (Rupr. & Maxim.) Maxim. leaves (ESL) have long been people’s favorite as a natural edible green vegetable, in which phenols and saponins are the main characteristic and bioactive components. This study was first carried out to comprehensively analyze the phenols and saponins in ESL, including phytochemical, qualitative, quantitative, and bioactivity analysis. The results showed that 30 compounds, including 20 phenolic compounds and 7 saponins, were identified. Twelve of them were isolated from Eleutherococcus Maxim. for the first time. In the qualitative analysis, 30 phenolic compounds and 28 saponins were accurately detected. Their characteristic cleavage processes were described by UPLC-QTOF-MS/MS. Ten representative ingredients were quantitated in 29 different regions via a 4000 QTRAP triple quadrupole tandem mass spectrometer (UPLC-QTRAP-MS/MS), and it was found that S19 (69.89 ± 1.098 mg/g) and S1 (74.28 ± 0.733 mg/g) had the highest contents of total phenols and saponins, respectively. The newly developed analysis method for the quantitative determination was validated for linearity, precision, and limits of detection and quantification, which could be applied to the quality assessment of ESL. In vitro experiment, the α-glucosidase inhibitory effect of the phenolic fraction was higher than others, indicating that the phenolic content may be related to the hypoglycemic activity. It was also suggested that ESL could be developed as a natural potential effective drug or functional food.

Glycosides and flavonoids from the extract of Pueraria thomsonii Benth leaf alleviate type 2 diabetes in high-fat diet plus streptozotocin-induced mice by modulating the gut microbiota

Twenty glycoside derivatives and nine flavonoids from the leaves of Pueraria (P. thomsonii) were isolated by column chromatography and characterized by nuclear magnetic resonance spectroscopy (NMR) and high performance liquid chromatography (HPLC). The contents of twenty glycosides and nine flavonoids from the extract of P. thomsonii leaf (PL) were 173.3 mg g^-1 and 134.7 mg g^-1, respectively. Two flavonoids with the highest content were robinin (49.28 mg g^-1) and puerarin (42.87 mg g^-1). Six flavonoids, i.e. puerarin, robinin, rutin, quercetin, quercitrin, and kaempferol showed more inhibitory effects against α-glucosidase than acarbose. PL could effectively increase the level of insulin, decrease the content of fasting blood glucose, reduce lipid accumulation in plasma, ameliorate oxidative injury and inflammation, and relieve liver and kidney damage in diabetic mice. Moreover, PL could increase intestinal probiotics to improve metabolic disorders caused by diabetes and decrease the level of Clostridium celatum to relieve inflammation. This study suggested that PL or its glycoside derivatives and flavonoids regulating glycolipid metabolism and inflammation levels might have the potential to be used to control type 2 diabetes.

Melissa officinalis: Composition, Pharmacological Effects and Derived Release Systems-A Review

Melissa officinalis is a medicinal plant rich in biologically active compounds which is used worldwide for its therapeutic effects. Chemical studies on its composition have shown that it contains mainly flavonoids, terpenoids, phenolic acids, tannins, and essential oil. The main active constituents of Melissa officinalis are volatile compounds (geranial, neral, citronellal and geraniol), triterpenes (ursolic acid and oleanolic acid), phenolic acids (rosmarinic acid, caffeic acid and chlorogenic acid), and flavonoids (quercetin, rhamnocitrin, and luteolin). According to the biological studies, the essential oil and extracts of Melissa officinalis have active compounds that determine many pharmacological effects with potential medical uses. A new field of research has led to the development of controlled release systems with active substances from plants. Therefore, the essential oil or extract of Melissa officinalis has become a major target to be incorporated into various controlled release systems which allow a sustained delivery.

Antiplasmodial and Cytotoxic Activities of Extract and Compounds from Ozoroa obovata (Oliv.) R. & A. Fern. var. obovata

Ozoroa obovata (Oliv.) R. & A. Fern. var. obovata found in KwaZulu-Natal in South Africa was investigated for phytochemical constituents, and for antiplasmodial and cytotoxic effects. The plant leaves were collected from the University of KwaZulu-Natal (UKZN) arboretum on the Pietermaritzburg Campus, in March 2019. The inhibitory activity against 3D7 Plasmodium falciparum was determined using the parasite lactate dehydrogenase (pLDH) assay and cytotoxicity against HeLa cells was evaluated using the resazurin assay. The bioactive compounds were isolated by chromatographic purification and their structures were established with spectroscopic and spectrometric techniques. The plant leaf extract displayed significant antiplasmodial activity at 50 μg/mL and was also cytotoxic against HeLa cells. Chromatographic purification of the extract led to the isolation of two biflavonoids, four flavonoid glycosides, a steroid glycoside, and a megastigmene derivative. The compounds displayed antiplasmodial and antiproliferative activities at 50 μg/mL but the activity was substantially reduced at 10 μg/mL. The activities and compounds are being reported in O. obovata for the first time.

Two new triterpenoids from the leaves of Cyclocarya paliurus (Batalin) Iljinskaja

Two previously undescribed triterpenoids (1-2), along with thirteen known compounds (3-15) were isolated from a CHCl₃-soluble extract of the leaves of Cyclocarya paliurus. Their structures were established on the basis of chemical and spectroscopic approaches. These compounds were assessed for their therapeutic effects on diabetic nephropathy (DN)-evoked fibrosis through High-Glucose and transforming growth factor-β1 (TGF-β1) challenged HK-2 cells. Among them, compounds 3, 5 and 8 could remarkedly decrease the level of fibronectin to relieve DN with 27.66 ± 2.77%, 6.09 ± 0.57% and 17.74 ± 5.83% inhibition rate at 10 μM, 10 μM and 1 μM, respectively.

Traditional uses and pharmacological activities of the genus leea and its phytochemicals: A review

Objectives

Plants have been used as traditional medicine (TM) since ancient times and TM remains an effective treatment option in the primary health care system in developing countries, including Bangladesh. There are several reasons to use plants as TM, which are cheaply and easily available and have a cultural heritage of their uses across generations. Leea, a genus of the Vitaceae family, possesses a large number of medicinal plants. In this review, the literature data on the traditional uses and pharmacological activities of Leea species and their phytochemicals are compiled. All the information was collected from the scientific databases.

Results

Leea species are endemic that have opened a promising research field to identify new leads against different diseases. Leea contains approximately 70 species, which are widely distributed throughout the Northern and Eastern Australia, South and Southeast Asia and parts of Africa. The Leea plants are used traditionally in different ailments such as fever, diarrhea, dysentery, joint pain, rheumatism, diabetes, bone fracture, body ache, wound, sexual disorders, and so on. The majority of the Leea species are the medicinal plants, which have anticancer, cytotoxic, antimicrobial, antidiabetic, hepatoprotective, cardiovascular, and CNS activity. Moreover, phytochemicals such as flavonoids, glycosides, phenols, terpenoids, steroids, volatile oils, alkaloids, proteins, quinine derivatives, tannins, saponins, and many other organic compounds have been reported in the Leea species (Leea indica, Leea macrophylla, Leea asiatica, Leea aequata, Leea rubra and Leea guineensis). The presence of phytochemicals and the in vitro and in vivo biological activities reported of these plants support their use as TM. Though original research articles related to the Leea genus are available, supportive reviews on phytochemicals and pharmacological activities remain scarce.

Conclusion

Leea species are used as TM in different ailments and have a real interest in their diverse pharmacological properties. Also, Leea species contain a remarkable number of bioactive compounds. This review has provided a comprehensive report on the plants of Leea genus to identify its therapeutic potential and future prospects for betterment research. However, chemical and biological investigations of several species of Leea genus remain unexplored. Therefore, further studies on these species are necessary, especially regarding pharmacological properties, isolation of the compounds and mechanism of action for the development of new drugs.

Preparative isolation of 1,1-diphenyl-2-picrylhydrazyl inhibitors from Ribes himalense using medium-pressure and two-dimensional reversed-phase/reversed-phase liquid chromatography guided by an online HPLC-1, 1-diphenyl-2-picrylhydrazyl assay

The lack of suitable chromatographic purification methods makes it a challenge to effectively isolate the chemical components of traditional Tibetan medicines. Ribes himalense is a rarely studied Tibetan medicine, reputed to have free radical-scavenging effects. In the present work, we utilized it as a model herb to highlight an approach for the separation of 1,1-diphenyl-2-picrylhydrazyl inhibitors via medium-pressure chromatography and two-dimensional reversed-phase/reversed-phase interaction liquid chromatography under the guidance of an online high-performance liquid chromatography-1,1-diphenyl-2-picrylhydrazyl assay. Finally, we obtained two free radical inhibitors (>95% purity) from the R. himalense extract. This is the first report of the rapid isolation of these free radical inhibitors from R. himalense. This method can be useful in quality standard assessment and further pharmacological activity research, and may be used as a reference for the composition research of various natural products.

Two new phenylpropanoid glycosidic compounds from the pseudobulbs of Pleione bulbocodioides and their hepatoprotective activity

Two new phenylpropanoid glycosidic compounds (a pair of epimers), named pleionosides K (1) and L (2), were isolated from the pseudobulbs of Pleione bulbocodioides (Franch.) Rolfe. Their structures, including absolute configurations, were elucidated by a combination of MS, NMR data, chemical methods and the comparison of experimental and calculated electronic circular dichroism (ECD). Their possible biosynthetic pathway was discussed in the text. Furthermore, the two compounds exhibited moderate hepatoprotective activity against N-acetyl-p-aminophenol (APAP)-induced HepG2 cell damage in in vitro assays, with cell survival rates of 25.83% and 28.82% at 10 μM, respectively, and antioxidant effect against H₂O₂-induced toxicity in human SK-N-SH cell, with increasing viability at 10 μM of 24.9% and 34.6%, respectively.

Bioassay guided isolation of mosquito biting deterrent compounds from Strumpfia maritima

BACKGROUND

In our natural products screening program against mosquitoes, we screened ethanolic extract of Strumpfia maritima Jacq. which showed high biting deterrent activity in Klun and Debboun (K&D) bioassays against Aedes aegypti L. Through bioguided fractionation we isolated six compounds from the active fractions. The extract and pure compounds were evaluated for larvicidal and biting deterrent activity against Aedes aegypti.

RESULTS

Ethanolic extract with proportion not biting (PNB) value of 0.8 ± 0.08 provided biting deterrent activity similar to N,N-dimethyl-m-toluamide (DEET) (PNB = 0.9 ± 0.05) against Ae. aegypti. Five out of eight fractions, prepared through bioassay-guided fractionation, showed biting deterrent activity similar to DEET. Six compounds were isolated from active fractions and characterized as squalene, ursolic acid, betulonic acid, cabraleone, ursolic acid acetate, and 27-p-E-coumaroyloxyursolic acid. The biting deterrent activity of ursolic acid acetate (biting deterrence index, BDI = 0.85), cabraleone (BDI = 0.79), and ursolic acid (BDI = 0.78) was similar to DEET against Ae. aegypti. Strumpfia maritima extract did not show larvicidal activity at the highest screening dose of 125 ppm in the larvicidal bioassay.

CONCLUSION

The ethanolic extract and pure compounds showed biting deterrent activity against Ae. aegypti. The high biting deterrent activity of ursolic acid acetate and cabraleone indicated a great potential for these natural compounds to be developed as mosquito repellents. © 2020 Society of Chemical Industry.

Phytochemical Study of Stem and Leaf of Clausena lansium

Clausena lansium Lour. Skeels (Rutaceae) is widely distributed in South China and has historically been used as a traditional medicine in local healthcare systems. Although the characteristic components (carbazole alkaloids and coumarins) of C. lansium have been found to possess a wide variety of biological activities, little attention has been paid toward the other components of this plant. In the current study, phytochemical analysis of isolates from a water-soluble stem and leaf extract of C. lansium led to the identification of 12 compounds, including five aromatic glycosides, four sesquiterpene glycosides, two dihydrofuranocoumarin glycosides, and one adenosine. All compounds were isolated for the first time from the genus Clausena, including a new aromatic glycoside (1), a new dihydrofuranocoumarin glycoside (6), and two new sesquiterpene glycosides (8 and 9). The phytochemical structures of the isolates were elucidated using spectroscopic analyses including NMR and MS. The existence of these compounds demonstrates the taxonomic significance of C. lansium in the genus Clausena and suggests that some glycosides from this plant probably play a role in the anticancer activity of C. lansium to some extent.