Leonard Williams

Dr. Leonard Williams

Center for Excellence in Post-Harvest Technologies, The North Carolina Research Campus, 500 Laureate Way, Kannapolis, NC 28081, USA.
orcid

Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
1 January 2017 in Journal of Traditional and Complementary Medicine
Verified
Journal Article
Open access
YJYogini S. Jaiswal
Yogini S. Jaiswal
LWLeonard Williams
Leonard Williams
Ayurveda is considered as one of the oldest of the traditional systems of medicine (TSMs) accepted worldwide. The ancient wisdom in this traditional system of medicine is still not exhaustively explored. The junction of the rich knowledge from different traditional systems of medicine can lead to new avenues in herbal drug discovery process. The lack of the understanding of the differences and similarities between the theoretical doctrines of these systems is the major hurdle towards their convergence apart from the other impediments in the discovery of plant based medicines. This review aims to bring into limelight the age old history and the basic principles of Ayurveda. This would help the budding scholars, researchers and practitioners gain deeper perspicuity of traditional systems of medicine, facilitate strengthening of the commonalities and overcome the challenges towards their global acceptance and harmonization of such medicinal systems.

1 March 2021 in Journal of Controlled Release
Verified
Journal Article
Open access
RDRana Delshadi
Rana Delshadi
ABAkbar Bahrami
Akbar Bahrami
David Julian McClementsDavid Julian McClements
David Julian McClements
MMMatthew D. Moore
Matthew D. Moore
LWLeonard Williams
Leonard Williams
The COVID-19 pandemic has resulted in unprecedented increases in sickness, death, economic disruption, and social disturbances globally. However, the virus (SARS-CoV-2) that caused this pandemic is only one of many viruses threatening public health. Consequently, it is important to have effective means of preventing viral transmission and reducing its devastating effects on human and animal health. Although many antivirals are already available, their efficacy is often limited because of factors such as poor solubility, low permeability, poor bioavailability, un-targeted release, adverse side effects, and antiviral resistance. Many of these problems can be overcome using advanced antiviral delivery systems constructed using nanotechnology principles. These delivery systems consist of antivirals loaded into nanoparticles, which may be fabricated from either synthetic or natural materials. Nevertheless, there is increasing empHasis on the development of antiviral delivery systems from natural substances, such as lipids, phospholipids, surfactants, proteins, and polysaccharides, due to health and environmental issues. The composition, morphology, dimensions, and interfacial characteristics of nanoparticles can be manipulated to improve the handling, stability, and potency of antivirals. This article outlines the major classes of antivirals, summarizes the challenges currently limiting their efficacy, and highlights how nanoparticles can be used to overcome these challenges. Recent studies on the application of antiviral nanoparticle-based delivery systems are reviewed and future directions are described.

1 September 2011 in Journal of Medicinal Food
Verified
Journal Article
Open access
MFMarjorie Fullerton
Marjorie Fullerton
JKJanak Khatiwada
Janak Khatiwada
JJJacqueline U. Johnson
Jacqueline U. Johnson
SDShurrita Davis
Shurrita Davis
LWLeonard Williams
Leonard Williams
The use of medicinal plants as natural antimicrobial agents is gaining popularity. Sorrel ( Hibiscus sabdariffa ) is widely used for the treatment of diseases. The objective of this study was to investigate the antimicrobial activity of sorrel on Escherichia coli O157:H7 isolates from food, veterinary, and clinical samples. Phenolics of the calyces were extracted from 10 g of ground, freeze-dried samples using 100 mL of 80% aqueous methanol. Concentrations of 10%, 5%, and 2.5% methanol extract of sorrel were investigated for its antimicrobial activity. Inhibition zones were indicated by a lack of microbial growth due to inhibitory concentrations of sorrel diffused into semisolid culture medium beneath the sorrel-impregnated disk. The results of this experiment showed that the most potent sorrel concentration was 10%, then 5%, and finally 2.5%. The overall mean zone of inhibition for the sorrel extract was 12.66 mm for 10%, 10.75 mm for 5%, and 8.9 mm for 2.5%. The highest inhibition zones (11.16 mm) were observed in veterinary samples, and the lowest (10.57 mm) in the food samples. There were significant ( P <.05) differences among mean zones of inhibition found in the food, veterinary, and clinical sources. Based on the source of samples and concentration of sorrel extract, the lowest mean inhibition was 7.00±0.04 mm from clinical samples, and the highest was 15.37±0.61 mm from a food source. These findings indicated that sorrel was effective at all levels in inhibiting E. coli O157:H7; thus it possesses antimicrobial activity and hold great promise as an antimicrobial agent.

2 October 2022 in Plants
Verified
Journal Article
Open access
PDF file
MMMohamed Mahmoud
Mohamed Mahmoud
AAAmira A. Ayad
Amira A. Ayad
HAHend S. M. Abdel-Aziz
Hend S. M. Abdel-Aziz
LWLeonard Williams
Leonard Williams
RERasha Mahmoud Sayed Hassan El-Shazoly
Rasha Mahmoud Sayed Hassan El-Shazoly
Emad AbdeldaymEmad Abdeldaym
Emad Abdeldaym
Nano-fertilizers are a new tool that can be used to address plant production challenges, and it addresses such nutrient deficiencies through smart agriculture approaches. Iron (Fe) is a vital element for several metabolic and physiological processes; however, Fe deficiency is common in poorly fertile soils (sand soil) and in arid areas. Therefore, additional research is required to select the most efficient form of iron absorbance. This research was implemented on broad bean plants (Vicia faba L. var. major Harz) to examine the impact of three iron sources: nano-iron (FeNPs, T1), iron sulfate (T2), and chelated iron (T3) as a foliar spray on the morphological properties, physiological attributes, and nutritional status of these plants compared to the untreated plants (control). The obtained results showed that foliar spraying with FeNPs, chelated iron and sulphate iron fertilizers increased plant height by 35.01%, 26.2, and 20.4%; leaf area by 38.8%, 18.3%, and 8.1%; the fresh weight of the plant by 47%, 32.8%, and 7.3%; the dry weight of the plant by 52.9%, 37.3%, and 11.2%; and the number of branches by 47%, 31.3%, and 25.6 %, respectively, compared to the control treatment (CT). Furthermore, the application of FeNPs, chelated iron, and sulphate iron fertilizers improved the number of pods by 47.9%, 24.8%, and 6.1%; the number of seeds by 32.8%, 7.9%, and 2.8%; and seed weight by 20.8%, 9.1%, and 5.4%, compared to control treatment (CT). Additionally, foliar application of FeNPs showed the highest values of photosynthesis rate (Pn), water-use efficiency (WUE), total chlorophyll, and phytohormones (IAA, GA3) compared to all the other treatments. The anatomical structure revealed an enhancement of leaf size and thickness (epidermis cells and mesophyll tissue) affected by FeNPs treatment compared to other treatments. Foliar application of FeNPs also improved the total content of carbohydrates, crude protein, element content (N, P, K, Ca, Na, Fe, Zn, Mn, and Cu), and some amino acids such as lysine, arginine, phenylalanine, isoleucine, and tyrosine in the seeds of broad beans. Based on the above results, the maximum values of all tested measurements were observed when FeNPs were used as the foliar spraying followed by chelated and sulphate iron fertilizers. Therefore, these findings suggest that using FeNPs, as a foliar treatment, could be a promising strategy for reducing the Fe deficiency in sandy soil and enhancing plant growth, pod yield, and pod quality of broad bean plants in addition to being environmentally favored in arid areas.

30 May 2019 in Molecules
Verified
Journal Article
Open access
PDF file
RCRui Chen
Rui Chen
HLHuo Lini
Huo Lini
YJYogini Jaiswal
Yogini Jaiswal
JHJiayong Huang
Jiayong Huang
ZZZhen Guo Zhong
Zhen Guo Zhong
ZYZhenshuo Yan
Zhenshuo Yan
Background: Acridine and thiourea derivatives are important compounds in medicinal chemistry due to their diverse biological properties including anticancer and antimicrobial effects. However, literature reveals some side effects associated with use of acridines. It is suggested that hybrid molecules may reduce the side effects and enhance the beneficial properties due to synergistic activity. The objectives of the present study are to synthesize and evaluate the anticancer and antimicrobial properties of new hybrids of acridine thiosemicarbazides derivatives. Results: The structures of the synthesized compounds 4a–4e were elucidated by MS and NMR spectra. In antimicrobial assay, Compound 4c exhibited potent antimicrobial activity compared to the other four compounds. In anticancer studies, we observed that compounds 4a, 4b, 4d and 4e exhibited high cytotoxicity against the MT-4 cell line, with IC50 values of 18.42 ± 1.18, 15.73 ± 0.90, 10.96 ± 0.62 and 11.63 ± 0.11 μM, respectively. The evaluation of anticancer effects, and the associated mechanism reveals that, the anticancer activities may be related to Topo I inhibitory activity, apoptosis and cell-cycle. Molecular docking studies revealed that the presence of planar naphtho-fused rings and a flexible thiourea group together, could improve DNA-intercalation and inhibition of DNA-Topo I activity. Conclusions: The results of this study demonstrate that the rational design of target derivatives as novel antimicrobial or antitumor leads is feasible.

1 November 2019 in Food Chemistry
Verified
Journal Article
Closed access
RBRishipal R. Bansode
Rishipal R. Bansode
PRPriscilla D. Randolph
Priscilla D. Randolph
NPNathalie J. Plundrich
Nathalie J. Plundrich
MLMary Ann Lila
Mary Ann Lila
LWLeonard Williams
Leonard Williams