New labdane diterpenes from Leonurus cardiaca

An analytical framework combining online high-performance liquid chromatography methodologies and biological properties of different extracts of Leonurus cardiaca

Little or no information is available concerning online high-performance liquid chromatography (HPLC) antioxidants and the antibiofilm effect of Leonurus cardiaca. Five distinct extractions of methanolic, ethyl acetate, dichloromethane, hexane, and water were obtained from L. cardiaca. In the online-HPLC-antioxidant analysis of all examined samples, rosmarinic acid emerged as the primary antioxidant, registering concentrations ranging from 6 to 15 ppm at wavelengths of 517 and 734 nm. Notably, the water extract exhibited robust antioxidant activity In vitro. Regarding acetylcholinesterase and butrylcholinesterase inhibition, the n-hexane extract exhibited superior inhibition with values of 3.08 and 5.83 galanthamine equivalent, respectively. Except for the water extract, all tested extracts (at a concentration of 20 μg/mL) exhibited substantial inhibitory activity against biofilm formation, in many cases superior to 80%, and reached even 94.52% against Escherichia coli. Although less vigorous, the extracts also acted against the mature biofilm (inhibition up 76.50% against Staphylococcus aureus). They could work against the metabolism inside an immature and mature biofilm, with inhibition percentages up to 93.18% (vs. Pseudomonas aeruginosa) and 76.50% (vs. Acinetobacter baumannii), respectively. Considering its significant antioxidants, enzyme inhibition, and antimicrobial activity, L. cardiaca emerges as a promising candidate for therapeutic potential.

Labdane diterpenoids from Lagopsis supina and their anti-neuroinflammatory activity

In this study, ten labdane-type diterpenoids 1-10 were isolated from a methanol extract of the whole plant Lagopsis supina, including three undescribed compounds 1-3. Their structures were determined by spectroscopic data analyses such as HR-ESI-MS, 1D, and 2D NMR, as well as comparison with literature data. At the same time, the absolute configuration of five compounds 2-5 and 10 was confirmed for the first time by the single crystal X-ray diffraction method. All the compounds were isolated from L. supina for the first time. The CCK-8 assay showed that all compounds had no significant damage to BV-2 microglial cells, and then screened their inhibitory effects of nitric oxide production stimulated by lipopolysaccharide in BV-2 microglial cells. The pharmacological results showed that compound 4 greatly inhibited LPS-stimulated NO release at the concentration of 10 μM, indicating that it has potential anti-neuroinflammatory activity.

New di-spirocyclic labdane diterpenoids from the aerial parts of Leonurus japonicus

Phytochemical investigation on the ethanol extract of a well-known medicinal herb Leonurus japonicus, led to the separation of 18 labdane type diterpenoids (1-18). Through comprehensive spectroscopic analyses and quantum chemical calculations, these compounds were structurally characterized as six new interesting 5,5,5-di-spirocyclic ones (1-6), two new (7 and 8) and six known (13-18) interesting 6,5,5-di-spirocyclic ones, a new rare 14,15-dinor derivative (9), and three new ones incorporating a γ-lactone unit (10-12). An in vitro neuroprotective assay in RSC96 cells revealed that compounds 7 and 12 exhibited neuroprotective activity in a concentration-dependent way, comparable to the reference drug N-acetylcysteine.

Phytochemical Profile and Biological Activities of Crude and Purified Leonurus cardiaca Extracts

Leonurus cardiaca L. (Lamiaceae) is a perennial herb distributed in Asia and Southeastern Europe and has been used in traditional medicine since antiquity for its role against cardiac and gynecological disorders. The polar extracts obtained from L. cardiaca aerial parts contain several compounds among which alkaloids, iridoids, labdane diterpenes, and phenylethanoid glycosides play a major role in conferring protection against the aforementioned diseases. On the other hand, the antioxidant activities and the enzyme inhibitory properties of these extracts have not yet been deeply studied. On the above, in the present study, crude and purified extracts were prepared from the aerial parts of L. cardiaca and have been chemically characterized by spectrophotometric assays and HPLC-DAD-MS analyses. Notably, the content of twelve secondary metabolites, namely phenolic acids (chlorogenic, caffeic, caffeoylmalic and trans-ferulic acids), flavonoids (rutin and quercetin), phenylethanoid glycosides (verbascoside and lavandulifolioside), guanidine pseudoalkaloids (leonurine), iridoids (harpagide), diterpenes (forskolin), and triterpenes (ursolic acid), has been determined. Furthermore, the extracts were tested for their antioxidant capabilities (phosphomolybdenum, DPPH, ABTS, FRAP, CUPRAC, and ferrous chelating assays) and enzyme inhibitory properties against cholinesterase, tyrosinase, amylase, and glucosidase. The purified extracts contained higher phytochemical content than the crude ones, with caffeoylmalic acid and verbascoside as the most abundant compounds. A linear correlation between total phenolics, radical scavenging activity, and reducing power of extracts has been found. Notably, quercetin, caffeic acid, lavandulifolioside, verbascoside, chlorogenic acid, rutin, and ursolic acid influenced the main variations in the bioactivities found in L. cardiaca extracts. Our findings provide further insights into the chemico-biological traits of L. cardiaca and a scientific basis for the development of nutraceuticals and food supplements.

Labdane-Type Diterpenoids from Leonurus japonicus and Their Plant-Growth Regulatory Activity

Thirteen new labdane-type diterpenoids 1-6, 9-11, 13, 14, 18, and 19 and seven known ones were isolated from the aerial parts of Leonurus japonicus. Compounds 1-5 represent rare examples of labdane-type diterpenoids, of which compounds 1-4 carry an N-chain linked at C-7 in their B-ring and compound 5 featured an α,β-unsaturated-γ-lactam moiety. The structures and absolute configurations of these new diterpenoids were characterized by a combination of spectroscopic techniques, X-ray crystallography, electronic circular dichroism, and calculated specific rotations. The plant-growth regulatory activity of these compounds on the growth of the roots and shoots of Lactuca sativa and Lolium perenne seedlings were evaluated. Compound 3 showed a broad-spectrum inhibitory activity with the inhibition rates ranging from 60 to 83.5% at a concentration of 200 μg/mL, which were as active as those of glyphosate. Compound 8 had a selective inhibitory activity against the growth of the roots of L. perenne seedlings with an inhibition rate of 81.7%. However, compounds 11 and 16 exhibited significant stimulation effects on the roots of L. sativa with stimulation rates of 59.8 and 65.3%, respectively. In addition, compounds 3 and 8 exhibited inhibitory effects on the germination of L. perenne seeds.

Medicinal Plants of the Family Lamiaceae in Pain Therapy: A Review

Recently, numerous side effects of synthetic drugs have lead to using medicinal plants as a reliable source of new therapy. Pain is a global public health problem with a high impact on life quality and a huge economic implication, becoming one of the most important enemies in modern medicine. The medicinal use of plants as analgesic or antinociceptive drugs in traditional therapy is estimated to be about 80% of the world population. The Lamiaceae family, one of the most important herbal families, incorporates a wide variety of plants with biological and medical applications. In this study, the analgesic activity, possible active compounds of Lamiaceae genus, and also the possible mechanism of actions of these plants are presented. The data highlighted in this review paper provide valuable scientific information for the specific implications of Lamiaceae plants in pain modulation that might be used for isolation of potentially active compounds from some of these medicinal plants in future and formulation of commercial therapeutic agents.

Phytochemistry and pharmacology of the genus Leonurus: The herb to benefit the mothers and more

Plants belonging to the genus Leonurus, also named motherwort, are traditionally used for anti-gynecological disorder in East Asia, and for sedative in Europe. Chemical investigation of the genus Leonurus not only enriched the natural products library, but also enlarged the pharmacological application of this traditional herb. In this review, we systematically summarized the structures of 259 compounds isolated from the genus Leonurus, featured with 147 labdane diterpenoids. The reported bioactivity studies up to 2017 are presented in the second part, with the main focus on the isolated compounds and also concerning the extracts. In addition to the traditional uterine contraction and sedative activity, recently the cardiovascular protection effect of leonurine has drawn most attention. Other than that, neuroprotection, anti-inflammation, anti-cancer, anti-platelet aggregation and many other activities have been assigned to various compounds from the genus Leonurus. Among 70 bioactivity references cited in this review, 57% of them were concentrated on two alkaloids (leonurine and stachydrine), whereas only 20% are about the 147 diterpenoids. Anti-inflammation is the major bioactivity discovered so far for the labdane diterpenoids from the genus Leonurus, whose further therapeutic potential still remains for exploration.

The Study of Analgesic Effects of Leonurus cardiaca L. in Mice by Formalin, Tail Flick and Hot Plate Tests

Leonurus cardiaca, commonly known as motherwort, is a member of the Lamiaceae family. It has a number of interesting biological activities, for example, sedative and hypotensive, antioxidant, anti-inflammatory, and antimicrobial activities. The aim of the present study was to investigate the effect of alcoholic extract of aerial part of Leonurus cardiaca on nociceptive response using formalin, tail flick, and hot plate tests in mice. The acute treatment of mice with an ethanolic extract at doses of 500 and 250 mg/kg by intraperitoneal administration produced a significant antinociceptive in the first and second phases of formalin test, respectively. The hot plate and tail flick tests showed an increase in the antinociceptive effect at dose 500 mg/kg. These results suggest that Leonurus cardiaca possesses central and peripheral antinociceptive actions.

Leonurus cardiaca L. (motherwort): a review of its phytochemistry and pharmacology

Leonurus cardiaca is a perennial plant indigenous to central Europe and Scandinavia, but it is also found in the area spanning temperate Russia to central Asia. It has been introduced to North America and has become established locally in the wild. Motherwort (Leonuri cardiacae herba) consists of aerial parts of Leonurus cardiaca gathered during the flowering period, dried at 35 °C and, according to European Pharmacopoeia 7th edition, should contain a minimum of 0.2% flavonoids, expressed as hyperoside. Compounds belonging to the group of monoterpenes, diterpenes, triterpenes, nitrogen- containing compounds, phenylpropanoids, flavonoids and phenolic acids, as well as volatile oils, sterols and tannins, have been identified in motherwort. Traditionally, extracts of the herb have been used internally, mainly for nervous heart conditions and digestive disorders. However, they have also been used for bronchial asthma, climacteric symptoms and amenorrhoea, as well as externally in wounds and skin inflammations. Mild negative chronotropic, hypotonic and sedative effects can be attributed to the herb and preparations thereof. Pharmacological studies have confirmed its antibacterial, antioxidant, anti-inflammatory and analgesic activity, as well as its effects on the heart and the circulatory system. Sedative and hypotensive activity has been demonstrated in clinical trials.

In vitro antiplasmodial activity and cytotoxicity of nine plants traditionally used in Gabon

AIM OF THE STUDY

As part of a project to identify new compounds active on malarial parasites, we tested the in vitro antiplasmodial activity of nine plants traditionally used to treat malaria symptoms in Haut-Ogooué Province, South-East Gabon.

MATERIALS AND METHODS

Dichloromethane and methanolic extracts of each plant were tested for their antiplasmodial activity on two chloroquine-resistant strains of Plasmodium falciparum (FCB and W2), based on lactate dehydrogenase activity. Cytotoxicity was assessed with the MTT test on MRC-5 human diploid embryonic lung cells.

RESULTS

The methanolic extract of Staudtia gabonensis and the dichloromethane extract of Adhatoda latibracteata showed high antiplasmodial activity (IC₅₀<1 μg/ml) and low cytotoxicity, with selectivity indexes of about 58.25 and 16.43, respectively. The methanolic extract of Monodora myristica and the dichloromethane extract of Afromomum giganteum also showed promising activity (1<IC₅₀<10 μg/ml) and low cytotoxicity, with selectivity indexes about 15.70 and 12.48, respectively. Dichloromethane extracts of Monodora myristica and Leonotis Africana showed moderate activity (10<IC₅₀<40 μg/ml), with selectivity indexes about 6.07 and 28.89, respectively. Both extracts of Culcasia lancifolia had IC₅₀ values of 10-40 μg/ml but high cytotoxicity (selectivity indexes <2.77). The methanolic extract of Dorstenia klaineana had moderate antiplasmodial activity (IC₅₀ around 17 μg/ml) but strong cytotoxicity (0.43 μg/ml), giving a selectivity index of about 0.03.

CONCLUSIONS

Most extracts of nine selected plants traditionally used to treat malaria in Gabon had interesting antiplasmodial activity in vitro. This supports continued investigations of traditional medicines in the search for new antimalarial agents. The compounds responsible for the observed antiplasmodial effects are under investigation.

Antimalarial compounds isolated from plants used in traditional medicine

Objectives

This review covers the compounds with antiplasmodial activity isolated from plants published from 2005 to the end of 2008, organized according to their phytochemical classes. Details are given for substances with IC50 values ≤ 11 μM.

Key findings

Malaria is a major parasitic disease in many tropical and subtropical regions and is responsible for more than 1 million deaths each year in Africa. The rapid spread of resistance encourages the search for new active compounds. Nature and particularly plants used in traditional medicine are a potential source of new antimalarial drugs as they contain molecules with a great variety of structures and pharmacological activities.

Summary

A large number of antimalarial compounds with a wide variety of structures have been isolated from plants and can play a role in the development of new antimalarial drugs. Ethnopharmacological approaches appear to be a promising way to find plant metabolites that could be used as templates for designing new derivatives with improved properties.