Leucophyllum Frutescens Research Articles

RETRACTED: Ahmad et al. Neuroprotection against Aluminum Chloride-Induced Hippocampus Damage in Albino Wistar Rats by Leucophyllum frutescens (Berl.) I.M. Johnst. Leaf Extracts: A Detailed Insight into Phytochemical Analysis and Antioxidant and Enzyme Inhibition Assays. Front. Biosci. (Landmark Ed) 2023, 28(8), 184.

The Editors-in-Chief have retracted the article titled "[Neuroprotection against Aluminum Chloride-Induced Hippocampus Damage in Albino Wistar Rats by Leucophyllum frutescens (Berl.) I.M. Johnst. Leaf Extracts: A Detailed Insight into Phytochemical Analysis and Antioxidant and Enzyme Inhibition Assays]" ([1]) due to significant concerns regarding the reliability and integrity of the data presented. After the publication of the article, several issues were brought to our attention regarding the originality and authenticity of the visual data within the manuscript. Specifically, Figure 4 of the article contains images that are identical to those in the previously published papers [2, 3]. This duplication of images raises serious questions about the validity of the results and the adherence to ethical standards of research. Despite multiple attempts to contact the authors for an explanation and an opportunity to address these concerns, no satisfactory response was provided. Given the lack of accountability and the serious nature of the academic misconduct implied, the Editor-in-Chief, after careful consideration and in accordance with the publication's ethical guidelines, has decided to retract the article.

Green synthesis of silver and copper-doped zinc oxide nanoflowers using Leucophyllum frutescens leaf extract for photodegradation of methylene blue dye and antibacterial applications

This is the first report on biogenic synthesis of silver and copper-doped zinc oxide nanoflowers using Leucophyllum frutescens leaf extract for environmental and biomedical applications.

Exploration of Phenolic Content and Antioxidant Potential from Plants Used in Traditional Medicine in Viesca, Mexico

The medicinal plants of the desert can be a potential source of natural bioactive compounds with applications in health and food preservation. This work aimed to investigate the phenolic content and antioxidant potential of twenty-three plants from the arid zone of Viesca, Mexico. The antioxidant potential was determined by three methods (ABTS, FRAP, and DPPH). Two extraction methods and three different concentration levels (1:10 mg/mL, 1:25 mg/mL, and 1:50 mg/mL) were evaluated. According to the results, Turnera diffusa (Damiana), Gutierrezia sarothrae (Hierba de San Nicolas), and Leucophyllum frutescens (Cenizo) present the largest content of phenolic compounds and high antioxidant activity. The highest values of antioxidant activity were achieved using a solid/liquid ratio of 1:50 g/mL for T. diffusa and G. sarothrae and 1:25 mg/mL for L. frutescens. The maceration method was the most suitable for extracting antioxidant compounds from T. diffusa and L. frutescens, while ultrasound-assisted extraction was more efficient for G. sarothrae. The HPLC-MS analysis showed the presence of important phenolic compounds. This study shows for the first time that three plants that naturally grow in Viesca have great potential as a source of natural antioxidant compounds.

Neuroprotection against Aluminum Chloride-Induced Hippocampus Damage in Albino Wistar Rats by Leucophyllum frutescens (Berl.) I.M. Johnst. Leaf Extracts: A Detailed Insight into Phytochemical Analysis and Antioxidant and Enzyme Inhibition Assays.

A previously unstudied medicinal plant, Leucophyllum frutescens (Berland.) I.M. Johnst. (Scrophulariaceae) was investigated to evaluate its potential in preventing and treating neurodegenerative diseases, including Alzheimer's disease. Methanolic leaf extract (MELE) and its fractions (HELE, CHLE, and BULE) were evaluated for their polyphenolic content and antioxidant activity by five different methods, including in vitro enzyme inhibition assays, which are clinically linked to neurodegenerative diseases. The potentially active n-butanol fraction (BULE) was further evaluated for its neuroprotective effects using an albino rat animal model and phytoconstituents profiling using Liquid chromatography with tandem mass spectrometry (LC-MS/MS), and in silico molecular docking by Maestro® Schrödinger. The n-butanol fraction (BULE) in the hydroalcoholic leaf extract exhibited the highest total phenolic content (230.435 ± 1.575 mg gallic acid equivalent gm-1± SD). The chloroform leaf extract exhibited the highest total flavonoid content (293.343 ± 3.756 mg quercetin equivalent gm-1± SD) as well as the highest antioxidant content, which was equivalent to Trolox, with five assay methods. Similarly, the chloroform and n-butanol fractions from the hydroalcoholic leaf extract significantly inhibited human acetylcholinesterase and butyrylcholinesterase with their IC50 values of 12.14 ± 0.85 and 129.73 ± 1.14 µg∙mL-1, respectively. The in vivo study revealed that BULE exhibited a significant neuroprotective effect at doses of 200 and 400 mg/kg/day in an aluminum chloride-induced neurodegenerative albino rat model. The LC-MS/MS analysis of BULE tentatively confirmed the presence of biologically active secondary metabolites, such as theobromine, propyl gallate, quercetin-3-O-glucoside, myricetin-3-acetylrhamnoside, isoquercitrin-6'-O-malonate, diosmetin-7-O-glucuronide-3'-O-pentose, pinoresinol diglucoside, asarinin, eridictoyl, epigallocatechin, methyl gallate derivative, and eudesmin. The results from the computational molecular docking of the identified secondary metabolites revealed that diosmetin-7-O-glucuronide-3'-O-pentose had the highest binding affinity to human butyrylcholinesterase, while isoquercetin-6'-O-malonate had the highest to human acetylcholinesterase, and pinoresinol diglucoside to human salivary alpha-amylase. The present study concluded a need for further exploration into this medicinal plant, including the isolation of the bioactive compounds responsible for its neuroprotective effects.

Hepatoprotective Activity, In Silico Analysis, and Molecular Docking Study of Verbascoside from Leucophyllum frutescens in Rats with Post-Necrotic Liver Damage

There is an urgent need for scientists to verify the pharmacological properties of medicinal plants. Leucophyllum frutescens (Lf) belongs to the family Scrophulariaceae, and it is used in the treatment of airway diseases such as cough, tuberculosis, and asthma. The methanolic extract of the aerial parts of Lf allows for the isolation and identification of verbascoside (Vb). This study aimed to evaluate the hepatoprotective effect of Vb, a caffeoyl phenylethanoid glycoside (CPG), on post-necrotic liver damage induced by thioacetamide (TA) via in vivo and in silico studies, with the latter considering a cancerous process. The aerial parts of Lf were extracted by maceration using hexane methanol (5 L/500 g/8 days). Vb was isolated from methanol extract at approximately 30%. Wistar rats were intragastrically pretreated or not with a single dose of Vb (20 mg/kg) for four days. On the fourth day, a single dose of TA (6.6 mmol/kg) was intraperitoneally injected. Blood samples and parameters related to liver damage, like AST and ALT, were obtained. Vb significantly reduced the level of liver injury following thioacetamide-induced necrosis. This was corroborated by in silico assay and docking studies, demonstrating that Vb can interact with a HeLa target through hydrogen bonds and electrostatic interactions, achieving better performance than commercial chemotherapeutic Taxol®, by 0.34 kcal/mol. AST and ALT were significantly lower in the rats pretreated with Vb. Furthermore, Vb did not induce cytotoxicity and had a median lethal dose (LD50) greater than 5000 mg/kg. These results suggest that Vb may be used as an alternative to reduce liver damage.

Synergetic effect of Leucophyllum frutescens and Ehretia microphylla dyes in enhancing the photovoltaic performance of dye-sensitized solar cells.

The use of new natural dyes derived from Leucophyllum frutescens and Ehretia microphylla as well as their combination in dye-sensitized solar cells (DSSCs) has been explored for the first time in the current work. The primary pigments that sensitize the semiconductor TiO2 films were found to be carotenoid, anthocyanin, and chlorophyll. Pigments from Leucophyllum frutescens and Ehretia microphylla were designated as LF and EM, and their mixture blended at volume percent of 50:50, 75:25, and 25:75 were labeled as LE1, LE2, and LE3, respectively. The absorption range, emission intensities, and the functional groups of the dyes and dye-loaded TiO2 photo-anode films were analyzed using ultraviolet-visible, photoluminescence and Fourier transform infrared spectroscopy. The surface morphology of bare and sensitized TiO2 films was identified through scanning electron microscopy (SEM). To evaluate the photovoltaic performance of the fabricated devices, the current-voltage characteristics, electrochemical impedance spectroscopy analysis and incident photon-to-current conversion efficiency measurements were performed. The study found that the co-sensitized cell LE2 outperformed both single and mixed dye-based cells, achieving a maximum conversion efficiency of 1.33% with a Voc of 516mV and a Jsc of 2.55mAcm-2. This synergetic effect of natural dyes proved the superior performance of DSSCs with co-sensitization.

Leucophyllum frutescens mediated synthesis of silver and gold nanoparticles for catalytic dye degradation.

The application of nanotechnology is gaining worldwide attention due to attractive physico-chemical and opto-electronic properties of nanoparticles that can be also employed for catalytic dye degradation. This study reports a phytogenic approach for fabrication of silver (AgNPs) and gold nanoparticles (AuNPs) using Leucophyllum frutescens (Berl.) I. M. Johnst (Scrophulariaceae) leaf extract (LFLE). Development of intense dark brown and purple color indicated the synthesis of AgNPs and AuNPs, respectively. Further characterization using UV-visible spectroscopy revealed sharp peak at 460 nm and 540 nm for AgNPs and AuNPs, respectively that were associated to their surface plasmon resonance. High resolution transmission electron microscope (HRTEM) revealed the spherical shape of the AgNPs, whereas anisotropic AuNPs were spherical, triangular and blunt ended hexagons. The majority of the spherical AgNPs and AuNPs were ∼50 ± 15 nm and ∼22 ± 20 nm, respectively. Various reaction parameters such as, metal salt concentration, temperature and concentration of the leaf extract were optimized. Maximum synthesis of AgNPs was obtained when 5 mM for AgNO3 reacted with 10% LFLE for 48 h at 50°C. Likewise, AuNPs synthesis was highest when 2 mM HAuCl4 reacted with 10% LFLE for 5 h at 30°C. Energy dispersive spectroscopy (EDS) showed phase purity of both the nanoparticles and confirmed elemental silver and gold in AgNPs and AuNPs, respectively. The average hydrodynamic particles size of AgNPs was 34.8 nm while AuNPs was 140.8 nm as revealed using dynamic light scattering (DLS) that might be due to agglomeration of smaller nanoparticles into larger clusters. ZETA potential of AgNPs and AuNPs were 0.67 mV and 5.70 mV, respectively. X-ray diffraction (XRD) analysis confirmed the crystallinity of the nanoparticles. Fourier transform infrared spectroscopy (FTIR) confirmed that various functional groups from the phytochemicals present in LFLE played a significant role in reduction and stabilization during the biogenic synthesis of the nanoparticles. The bioreduced AgNPs and AuNPs catalytically degraded Rhodamine B dye (RhB) in presence of UV-light with degradation rate constants of 0.0231 s−1 and 0.00831 s−1, respectively. RhB degradation followed a first order rate kinetics with 23.1 % and 31.7% degradation by AgNPs and AuNPs, respectively.

GC–MS profiling, phytochemical and biological investigation of aerial parts of Leucophyllum frutescens (Berl.) I.M. Johnst. (Cenizo)

Leucophyllum frutescens (Berl.) I.M. Johnst has been used as a crude drug for treating various respiratory ailments, dysentery, cataract and liver disorders in the folk medicine systems by the inhabitants of America and Mexico. The Phytochemical and biological investigation was established by spectrophotometrically and chemical profiling was performed by GC–MS analysis. The chemical profiling by GC–MS analysis revealed that HELE majorly contains 9-octadecenoic acid (Z)-, methyl ester, pentadecanoic acid, 14-methyl-, methyl ester, 2,6-bis(3,4-methylenedioxyphenyl)-3,7-dioxabicyclooctane, (+)-sesamin, 9,12-octadecadienoic acid, methyl ester, 9,12,15-octadecatrienoic acid, ethyl ester, (Z,Z,Z)-, n-hexadecanoic acid, hexadecanoic acid, ethyl ester, phytol, methyl stearate, cyclohexanone, 1H,3H-Furo[3,4-c]furan, 1,4-bis(3,4-dimethoxy phenyl)tetrahydro-, [1R-(1.alpha.,3a.alpha.,4.alpha.,6a.alpha.)]-, and squalene. Strong inhibition of α-glucosidase and urease enzymes was observed by HELE (IC50 0.3321 mg.mL−1) and CHLE (IC50 4.711 mg.mL−1) extracts, respectively. Phytochemical quantification revealed high TPC by BULE (189.369±1.393 mg GA.Eq.gm−1 DE ± S.D) and high TFC by CHLE (232.458±1.589 mg Qu.Eq.gm−1 DE ± S.D). CHLE presented with highest antioxidant content equivalent to Trolox, by five different spectrophotometric methods such as TAA, DPPH, TEAC, FRAP, and CUPRAC. The study concludes that L. frutescens possesses significant antioxidant, antidiabetic and cytotoxic activities indicating that L. frutescens as a potential candidate for discovery of novel phytochemical products and industrial applications.

Bio-Construction of CuO Nanoparticles Using Texas Sage Plant Extract for catalytical degradation of Methylene blue Via Photocatalysis

The theme of this research is to highlight the importance of green synthesis for nanomaterials preparation. In citing this statement, herein, we reported bio-synthesis of copper oxide (CuO) nanoparticles by Leucophyllum frutescens leaf extract-mediated reaction along with the study of morphological, optical, structural features and their photocatalytic dye degradation activity of synthesized nanoparticles. The formation of bio-mediated CuO nanoparticles was confirmed by the XRD having crystalline size of 27 nm and monoclinic structure, FTIR presenting absorption band at 673 cm−1. The phase purity was revealed from XRD as there is no extra peak for impurities. The CuO represents the absorption of UV radiations at 380 nm upon UV-DRS studies and band gap energy of 1.48 eV. The morphological studies wereperformed by the FESEM and TEM, both characterized that CuO nanoparticles are spherical in shape. The particle size calculated by particle distribution through FESEM and SEM micrographs was ∼ 25 nm which is in accordance with the crystalline size calculated by XRD. The formation of CuO nanoparticles and phase purity was further validated by the EDX analysis. The metallic existence, phase purity and valency of synthesized nanoparticles confirmed by the XPS. The photocatalytic degradation of methylene blue was studied by CuO under irradiation of visible light. The synthesized CuO degraded the cationic dye in 120 min with the degradation efficiency of 88%. Thus, the proposed work suggests the synthesis of metal oxides nanoparticles via green synthesis is very cost effective and ecofriendly process. The green synthesized CuO nanoparticles are efficient photocatalysts for detection and remediation of organic environmental pollutants in water bodies, presenting their potential towards development of wastewater applications.

Influence of Planting dates, Cutting types and IBA Concentrations on Rooting of Silvery (Leucophyllum frutescens)

Influence of Planting dates, Cutting types and IBA Concentrations on Rooting of Silvery (Leucophyllum frutescens)

Biological Potential of Silver Nanoparticles Mediated by Leucophyllum frutescens and Russelia equisetiformis Extracts.

Awareness about environmental concerns is increasing, specially the pollution resulting from nanoparticles (NPs) production, which has led to great interest in the usage of biogenic agents for their fabrication. The current investigation used eco-friendly organic phytomolecules from Leucophyllum frutescens and Russelia equisetiformis leaves extract for the first time in the fabrication of silver NPs from silver ions and further an assessment of their biological activities was performed. The leaves extract from both plant sources were used as capping and reducing agents and added to AgNO3. The mixtures were observed for colour changes, and after a stable dark brown colour was obtained, the NPs were separated and further investigated using dynamic light scattering, transmission electron microscopy and energy-dispersive X-ray spectroscopy. The Fourier transform infrared spectroscopy technique was employed to determine the active organic ingredients in the plant extracts. The prepared NPs were tested against three cell lines (two cancer ones and one normal control) and the effects observed using TEM and confocal laser scanning microscopy (LSM). Antibacterial activity against two Gram positive and two Gram negative species was examined and the synergistic effect of the ampicillin-NPs conjugate was studied. Findings showed successful conversion of Ag ions into L-AgNPs and R-AgNPs achieved using L. frutescens and R. equisetiformis extracts, respectively. A mean size of 112.9 nm for L-AgNPs and 151.7 nm for R-AgNPs and negative zeta potentials were noted. TEM analysis showed spherical NPs and EDS indicated Ag at 3 keV. Reduction in cancer cell viability with low half-maximal inhibitory concentrations was noted for both tested NPs. Structural changes and apoptotic features in the treated cancer cell lines were noted by TEM and cell death was confirmed by LSM. Furthermore, higher antibacterial activity was noticed against Gram positive compared with Gram negative bacteria as well as high synergistic effect was noted for the Amp-NPs conjugate, specially against Gram positive bacteria. The current investigation has thus developed an eco-friendly NPs synthesis route by applying plant extracts to efficiently produce NPs endowed with potential cytotoxic and antibacterial capacity, which therefore could be recommended as new approaches to overcome human diseases with minimal environmental impact.

First Report of Powdery Mildew on Leucophyllum frutescens Caused by Podosphaera xanthii in Mexico.

Leucophyllum frutescens (Scrophulariaceae family), commonly known as Texas sage or cenizo, is an evergreen shrub native to southwestern United States and northern Mexico. This plant is commercially sold as a native, drought-tolerant ornamental. During the spring of 2019 and 2020, typical symptoms of powdery mildew were found on cenizo plants growing as ornamentals in urban areas in the municipality of Ahome, Sinaloa, Mexico. Disease incidence was 95% from a sampled population of 120 plants. Initial symptoms of powdery mildew developed as irregular white colonies on upper leaf surfaces which expanded as infections progressed. In severe infections, leaves became distorted, exhibiting premature defoliation. Microscopic examination showed nipple-shaped appressoria. Conidiophores (n= 30) were hyaline, cylindrical, erect, 89.4 to 134.2 μm long, and forming catenescent conidia. Foot-cells were cylindrical, 35.7 to 65.3 × 10.2 to 13.5 μm, followed by 1-3 shorter cells. Conidia (n= 100) were hyaline, ellipsoid to ovoid, 27.9 to 40.5 × 13.8 to 18.9 μm, containing distinct fibrosin bodies. Germ tubes were simple to forked and laterally produced from the middle of conidia. Chasmothecia were not found during the sampling period on the infected leaves. Based on morphological characteristics, the fungus was identified as Podosphaera xanthii (Braun and Cook 2012). A voucher specimen (accession no. FAVF219) was deposited in the Herbarium of the Faculty of Agronomy of El Fuerte Valley at the Autonomous University of Sinaloa (Juan Jose Rios, Sinaloa, Mexico). To further confirm the identification, total DNA was extracted, and the internal transcribed spacer (ITS) region was amplified by PCR using the primers ITS5/ITS4 (White et al. 1990) and sequenced. The resulting 503 bp sequence (GenBank accession no. MT624793) had 100% coverage and 100% identity to those of P. xanthii (MT568609-MT568611, MT472035, MT309699, MT250855, MT242593). A phylogenetic tree using the maximum parsimony (MP) and maximum likelihood (ML) methods and including published ITS sequences for Podosphaera species was obtained. Phylogenetic analyses revealed that ITS sequence from FAVF219 isolate was grouped into a clade with P. xanthii. Pathogenicity was demonstrated by gently dusting conidia from infected leaves onto 50 leaves of five healthy plants. Five non-inoculated plants served as controls. All plants were covered with polyethylene bags for 48 h to maintain high humidity and were maintained in a greenhouse at temperatures ranging from 20 to 35ºC. All inoculated plants developed similar symptoms to the original observations after 19 days, whereas no symptoms of powdery mildew were observed on control plants. The fungus present on the inoculated plants was morphologically identical to that originally observed on diseased plants, fulfilling Koch's postulates. This fungus has been reported infecting members of the Cucurbitaceae in Mexico (Félix-Gastélum et al. 2017; Farr and Rossman 2020). However, to our knowledge, this is the first report of P. xanthii causing powdery mildew on a member of Scrophulariaceae, specifically L. frutescens in Mexico and worldwide. Further studies for monitoring and control strategies of powdery mildew on Texas sage are required.

The biosynthesis of the anti-microbial diterpenoid leubethanol in Leucophyllum frutescens proceeds via an all-cis prenyl intermediate.

SUMMARYSerrulatane diterpenoids are natural products found in plants from a subset of genera within the figwort family (Scrophulariaceae). Many of these compounds have been characterized as having anti‐microbial properties and share a common diterpene backbone. One example, leubethanol from Texas sage (Leucophyllum frutescens) has demonstrated activity against multi‐drug‐resistant tuberculosis. Leubethanol is the only serrulatane diterpenoid identified from this genus; however, a range of such compounds have been found throughout the closely related Eremophila genus. Despite their potential therapeutic relevance, the biosynthesis of serrulatane diterpenoids has not been previously reported. Here we leverage the simple product profile and high accumulation of leubethanol in the roots of L. frutescens and compare tissue‐specific transcriptomes with existing data from Eremophila serrulata to decipher the biosynthesis of leubethanol. A short‐chain cis‐prenyl transferase (LfCPT1) first produces the rare diterpene precursor nerylneryl diphosphate, which is cyclized by an unusual plastidial terpene synthase (LfTPS1) into the characteristic serrulatane diterpene backbone. Final conversion to leubethanol is catalyzed by a cytochrome P450 (CYP71D616) of the CYP71 clan. This pathway documents the presence of a short‐chain cis‐prenyl diphosphate synthase, previously only found in Solanaceae, which is likely involved in the biosynthesis of other known diterpene backbones in Eremophila. LfTPS1 represents neofunctionalization of a compartment‐switching terpene synthase accepting a novel substrate in the plastid. Biosynthetic access to leubethanol will enable pathway discovery to more complex serrulatane diterpenoids which share this common starting structure and provide a platform for the production and diversification of this class of promising anti‐microbial therapeutics in heterologous systems.

Home-range analyses and habitat use by white-tailed deer females during the breeding season

There is little knowledge about the behavior strategies used by white-tailed deer (Odocoileus virginianus texanus) females with fawns. This study analyzed the variation in home range and the use of vegetation types by eight females during the breeding season in a brushland in northeastern Mexico and compared the strategies of females with and without fawns. Eight females were captured and radiotelemetry collars were fitted to them. We sampled two to three 24-hour cycles at 1-hour intervals monthly from April to October 1997 and 1998. In 1997 all females had fawns, whereas in 1998 some of these females had no fawns. This allowed comparing the strategies of females with and without offspring. The home range was significantly larger in females with fawns. In particular, no monthly variations in the home range were observed when females had fawns, while the home range was larger in August in females without fawns. Females preferred two of the seven habitat types (plant associations) studied, the ones dominated by Acacia-Prosopis and by Leucophyllum frutescens. Monthly variations were noted in both home-range size and use of plant associations when females were raising fawns. These data allow a better understanding of the behavioral strategies of females, which may contribute to the development of management strategies.

Quantitative Aspect of Leucophyllum frutescens Fraction before and after Encapsulation in Polymeric Nanoparticles.

The interest on plants has been focalized due to their biological activities. Extracts or fractions from plants in biodegradable polymeric nanoparticles (NP) provide many advantages on application studies. The encapsulation of the extract or fraction in NP is determined for the establishment of the test dose. HPLC method is an alternative to calculate this parameter. An analytical method based on HPLC for quantification of a hexane fraction from L. frutescens was developed and validated according to ICH. Different concentrations of the hexane fraction from leaves (HFL) were prepared (100–600 μg/mL). Linearity, limit of detection, limit of quantification, and intra- and interday precision parameters were determined. HFL was encapsulated by nanoprecipitation technique and analyzed by HPLC for quantitative aspect. The method was linear and precise for the quantification of the HFL components. NP size was 190 nm with homogeneous size distribution. Through validation method, it was determined that the encapsulation of components (1), (2), (3), and (4) was 44, 74, 86, and 97%, respectively. A simple, repeatable, and reproducible methodology was developed for the propose of quantifying the components of a vegetable material loaded in NP, using as a model the hexane fraction of L. frutescens leaves.

The rooting response of silvery (Leucophyllum frutescens) cuttings to different growing conditions and planting dates

The rooting response of silvery (Leucophyllum frutescens) cuttings to different growing conditions and planting dates

Phenology, Morphology and Variability in Pollen Viability of Four Woody Species (Cordiaboissieri, Parkinsonia texana, Parkinsonia aculeate and Leucophyllum frutescens) Exposed to Environmental Temperature in Linares, Northeast of Mexico

The present study has been undertaken on phenology, pollen morphology, and the effect of environmental temperatureon pollen viability of four woody species (Cordia boissieri, Parkinsonia texana, Parkinsonia aculeate and Leucophyllum frutescens) in northeast Mexico. These four species started flowering from March till June during this month they are in fruiting stage. Large variations were observed on pollen morphology with respect to form, size, and surface ornamentations of pollen grains. The species varied widely in pollen viability percentage in response to the prevailing environmental temperatures. Although, at 23°C the species showed high pollen viability, Cordia boissieru (81.22%), Parkinsonia aculeate (80.11), Parkinsonia texana (79.40). and Leucophyla frutescens 73.79%) but with an incease in temperature pollen viability decreased down to about 60%). The temperature 23°C was found to be favorable for optimum pollen viability (80%) of all the species studied. With an increase in temperature, C. boissieri showed drastic decrease in pollen viability, while the pollen viability remained more or less stable, but decreased at 32°C.

Leubethanol antimicobacterial activity improvement

The tuberculosis mainly caused by Mycobacterium tuberculosis (MTB) remains a worldwide major health problem. It represents the greatest killer worldwide due to a single infectious agent. According to the latest WHO report [1], in 2012, 8.6 million people fell ill with TB and 1.3 million died from TB. Over 95% of TB deaths occur in low- and middle-income countries, and it is among the top three causes of death for women aged 15 to 44. The use of established drugs like isoniazid, rifampicin and ethambutol (EMB), very useful and effective in the past, are ineffective against multiresistant strains (MRS-TB) and the co-infection TB-AIDS in addition to other causes, has promoted the emergence of resistant strains extremely (XDR-TB) [2]. These circumstances make necessary the development of new and more effective drugs. Research groups of the University of Salamanca (Spain) and of the Autonomous University of Nuevo Leon (Mexico), “Pharmaceutical Chemistry” and “Analytical Chemistry”, respectivily, have been working in recent years in the research and development of new molecules effective against MTB that could prevent the growth of normal and multi-drug resistant strains. Therefore, starting from natural [3] and synthetic (EMB) [4] models have obtained substances with more potent and selective anti-MTB activity. Based on the structure of the natural diterpene leubethanol chemical transformations to improve its antimycobacterial activity have been made. Leubethanol was conveniently isolated, purify and characterized from Leucophyllum frutescens root bark. Modifications on the aromatic ring (electron withdrawing groups), on the aliphatic chain (CHO, COOH, C = NOH, heterocycles) and also dimeric compounds were obtained. All the compounds were evaluated against H37Rv and MDR strains of MTB, some of them exceeded Leubetanol activity.

Medicinal Plants, an Important Reserve of Antimycobacterial and Antitubercular Drugs: An Update

Background: Tuberculosis is a global and serious Public Health problem due to the increase of multidrugresistant and extensively drug-resistant cases; as a result, diverse research groups worldwide are focusing their efforts on finding novel antituberculous agents that can provide greater effectiveness, less toxicity and having a specific mechanism of action, possibly being coadjuvants in the treatments currently prescribed. Methods: The present review covers the literature published concerning secondary metabolites of those Mexican medicinal plants and secondary metabolites isolated from them showing in vitro antimycobacterial activity with MIC <50 μg/mL against sensitive and MDR M. tuberculosis strains as well as against NTM strains. The review also includes a special section for those natural compounds or plant extracts with antitubercular activity evaluated an in vivo experimental tuberculosis model. Results: Some pure compounds with MIC<25 μg/mL are: 2-oxo-14-(3´,4´-methylenedioxyphenyl) tetradecane, 2- oxo-16-(3´,4´-methylenedioxyphenyl)hexadecane, 5,6-dehydro-7,8-dihydro methysticin, cepharanone B and piperolactam A (from Piper sanctum), suberosin (from Arracacia tolucensis) and leubethanol (from Leucophyllum frutescens). In addition, (-)-licarin A (from Aristolochia taliscana) was active against M. tuberculosis H37Rv, 12 MDR M. tuberculosis clinical isolates and four non-tuberculous mycobacteria. On the other hand, the antitubercular activity of (-)-licarin A, ursolic acid and oleanolic acid has been determined in a TB murine experimental in vivo model; (-)-licarin A reduces the bacterial lung load and the percentage of pneumonia in animals infected with M. tuberculosis H37Rv and MDR M. tuberculosis. The mixture of ursolic and oleanolic acids showed a significant reduction of bacterial loads and pneumonia in animals infected with M. tuberculosis H37Rv and MDR M. tuberculosis. Conclusion: Since (-)-licarin A, ursolic acid and oleanolic acid have been evaluated as antitubercular compounds, these metabolites are candidates proposed feasible to be proposed for development of antituberculosis drugs.

Total synthesis and structural confirmation of the antibacterial diterpene leubethanol

We report the total synthesis of leubethanol (1), a serrulatane compound that has recently been reported as having considerable antibacterial activity against multidrug-resistant bacteria, such as Staphylococcus aureus, and is of interest for applications in the control of bacterial biofilms in human medicine. Our synthetic route begins with (−)-isopulegol (4) and key steps include substrate directed hydroboration to generate the C1′ stereocentre and formation of the aromatic ring via the α-oxoketene-S,S-acetal intermediate 3. Overall the conversion of (−)-isopulegol (4) to leubethanol was achieved in 13 steps and an overall yield of 7%. Comparison of our spectroscopic data with those reported for leubethanol (1), isolated from Leucophyllum frutescens, verified the structure of the natural product.