Exploring the chemical characterization and insecticidal activities of Curcuma angustifolia roxb. leaf essential oils against three major stored product insects

Botanical pesticides are safe and widely used in pest management. Curcuma angustifolia belongs to the family Zingiberaceae and is a rhizomatous medicinal herb. Following rhizome harvesting, leaves are discarded as waste. However, they can be effectively utilized by extracting essential oils, which are potential biopesticides. The aim of the study is to evaluate the efficacy of the leaf essential oil of Curcuma angustifolia as a potential biopesticide against three stored grain pests, Lasioderma serricorne, Tribolium castaneum, and Callasobruchus chinensis, by their contact, fumigant, and repellent activities. The leaves yield 0.39 ± 0.02 % of oil by hydrodistillation. GC-MS/MS characterization identified curzerenone (18.37 %), geranyl-p-cymene (17.32 %), α-elemenone (13.59 %), eucalyptol (7.58 %) as the main constituents. When exposed to different concentrations of C. angustifolia oil, the test insect displayed noticeably high repellency rates. It also showed better contact toxicity at 24 h, LC50 = 0.22 mg/cm2 for cigarette beetle, LC50 = 0.64 mg/cm2 for red flour beetle, LC50 = 0.07 mg/cm2 for pulse beetle) and fumigation toxicities (LC50 = 10.8 mg/L air at 24 h, for cigarette, LC50 = 29.5 mg/L air for red flour beetle, LC50 = 7.9 mg/L air for pulse beetle). Additionally, a phytotoxicity study was done on paddy seeds, and the results showed no effect on seed germination or seedling growth. It was evident from this study that C. angustifolia oil from waste leaves can be utilized as a botanical pesticide to manage the adults of these storage pests.

Chemical Composition and Biological Activities of the Essential Oil from Citrus reticulata Blanco Peels Collected from Agrowastes

Citrus fruits have a thick outer coat which is often discarded due to its low economic value and usually contributes to the waste. So this work focused on exploring the potential pharmacological properties of the discarded citrus peels. In the present study, we extracted the essential oil from peel wastes of Citrus reticulata Blanco (CREO) from the local market. The antioxidant, antibacterial, and anticancer properties of essential oil were evaluated. The CREO exhibited a strong antioxidant property with DPPH radical scavenging, ABTS radical scavenging, H2 O2 radical scavenging, Ferric reducing antioxidant power and for Lipid peroxidation inhibition respectively. Antibacterial properties of CREO was indicated against different pathogenic microbial strains like E. coli, P. aeruginosa, S. aureus, and S. enterica in terms of disc diffusion method and minimum inhibitory concentration (MIC). Further, anticancer properties studied on breast cancer cell lines MCF7 and MDA-MB-231 showed dose-dependent cytotoxicity with IC50 of 56.67±3.12 μg/mL and 76.44±2.53 μg/mL respectively. The GC-MS analysis of CREO revealed the presence of major compounds like S-limonene, α-pinene, α-myrcene, and cis-terpinene which might have played a significant role in strong antioxidant, antibacterial and anticancer properties. The study thus identified the potential health benefits of Citrus reticulata peel waste.

Extraction, Chemical Composition and Insecticidal Activities of Lantana camara Linn. Leaf Essential Oils against Tribolium castaneum, Lasioderma serricorne and Callosobruchus chinensis

Storage pests and the food spoilage they cause are problems of great concern. Using essential oil obtained from different plants as an insecticide against these storage pests can be considered an environmentally friendly pest management option. Lantana camara Linn. (family Verbenaceae) is a flowering species, and is also a noxious weed that can proliferate well in nearly all geographical habitats. A biopesticide derived from the essential oil extracted from this plant can offer an effective solution for controlling storage pests. The goal of this study is to extract and analyse the chemical composition of essential oil obtained from L. camara leaves, and assess its effectiveness as a bioactive substance against three storage pests: Tribolium castaneum, Lasioderma serricorne, and Callosobruchus chinensis. The yield of essential oil extracted from L. camara leaves was about 0.24 ± 0.014%. By employing the GC-MS technique, the major phytochemicals contained in L. camara leaf essential oil were identified as caryophyllene (69.96%), isoledene (12%), and ɑ-copaene (4.11%). The essential oil exhibited excellent fumigant toxicity (LC50 of 16.70 mg/L air for T. castaneum, 4.141 mg/L air for L. serricorne and 6.245 mg/L air for C. chinensis at 24 h), contact toxicity (LC50 of 8.93 mg/cm2 for T. castaneum, 4.82 mg/cm2 for L. serricorne and 6.24 mg/cm2 for C. chinensis after 24 h) along with effective repellent activity towards the test insects. In addition, the oil showed no significant phytotoxicity on the germination of paddy seeds. This presents the potential to utilize a weed in developing a biopesticide for effectively managing stored product insects because of its strong bioactivity.

Extraction and chemical characterisation of agro-waste from turmeric leaves as a source of bioactive essential oils with insecticidal and antioxidant activities

Turmeric (Curcuma longa L.) is a significant crop that has historically been used worldwide as a medicinal plant, spice, food colouring agent, and a significant ingredient in cosmetic industries. After harvesting rhizomes, leaves are considered waste material. This research study aims to extract and chemically characterise the essential oil from the leaves waste of turmeric with an evaluation of different insecticidal, antioxidant, and phytotoxic activities. Subsequently, the contact toxicity, fumigant toxicity, and repellent activity were evaluated against two key stored grain insect species. The gas chromatography-mass spectrometry (GC-MS) characterisation revealed that α-phellandrene (28.95%), 2-carene (16.51%), eucalyptol (10.54%) and terpinolene (10.24%) were the major chemical constituents. The study's findings on the insecticidal effects of essential oils extracted from turmeric leaves revealed noteworthy repellent, contact (at 24 h, LC50 = 6.51 mg/cm2 for Tribolium castaneum and LC50 = 4.74 mg/cm2 for Rhyzopertha dominica) and fumigant toxicities (at 24 h, LC50 = 2.57 mg/L air for T. castaneum and LC50 = 2.83 mg/L air for R. dominica), against two key stored grain insects. In addition, turmeric leaf essential oil showed notable antioxidant activity (IC50 = 10.04 ± 0.03 µg/mL for DPPH assay; IC50 = 14.12 ± 0.21 µg/mL for ABTS assay. Furthermore, a phytotoxicity study was carried out on stored paddy seeds and no toxic effects were found on germination rate and seedling growth. So, it might be expected that the essential oils extracted from the turmeric leaf waste could be valorised and demonstrate their potential as safe botanical insecticides against stored-product insects, with noble antioxidant properties.

Chemical Composition of the Cinnamomum malabatrum Leaf Essential Oil and Analysis of Its Antioxidant, Enzyme Inhibitory and Antibacterial Activities

Cinnamomum species are a group of plants belonging to the Lauraceae family. These plants are predominantly used as spices in various food preparations and other culinary purposes. Furthermore, these plants are attributed to having cosmetic and pharmacological potential. Cinnamomum malabatrum (Burm. f.) J. Presl is an underexplored plant in the Cinnamomum genus. The present study evaluated the chemical composition by a GC-MS analysis and antioxidant properties of the essential oil from C. malabatrum (CMEO). Further, the pharmacological effects were determined as radical quenching, enzyme inhibition and antibacterial activity. The results of the GC-MS analysis indicated the presence of 38.26 % of linalool and 12.43% of caryophyllene in the essential oil. Furthermore, the benzyl benzoate (9.60%), eugenol (8.75%), cinnamaldehyde (7.01%) and humulene (5.32%) were also present in the essential oil. The antioxidant activity was indicated by radical quenching properties, ferric-reducing potential and lipid peroxidation inhibition ex vivo. Further, the enzyme-inhibitory potential was confirmed against the enzymes involved in diabetes and diabetic complications. The results also indicated the antibacterial activity of these essential oils against different Gram-positive and Gram-negative bacteria. The disc diffusion method and minimum inhibitory concentration analysis revealed a higher antibacterial potential for C. malabatrum essential oil. Overall, the results identified the predominant chemical compounds of C. malabatrum essential oil and its biological and pharmacological effects.

Chemical Composition, Antioxidant, Anti-Bacterial, and Anti-Cancer Activities of Essential Oils Extracted from Citrus limetta Risso Peel Waste Remains after Commercial Use

Citrus plants are widely utilized for edible purposes and medicinal utility throughout the world. However, because of the higher abundance of the antimicrobial compound D-Limonene, the peel waste cannot be disposed of by biogas production. Therefore, after the extraction of D-Limonene from the peel wastes, it can be easily disposed of. The D-Limonene rich essential oil from the Citrus limetta risso (CLEO) was extracted and evaluated its radical quenching, bactericidal, and cytotoxic properties. The radical quenching properties were DPPH radical scavenging (11.35 ± 0.51 µg/mL) and ABTS scavenging (10.36 ± 0.55 µg/mL). There, we observed a dose-dependent antibacterial potential for the essential oil against pathogenic bacteria. Apart from that, the essential oil also inhibited the biofilm-forming properties of E. coli, P. aeruginosa, S. enterica, and S. aureus. Further, cytotoxicity was also exhibited against estrogen receptor-positive (MCF7) cells (IC₅₀: 47.31 ± 3.11 µg/mL) and a triple-negative (MDA-MB-237) cell (IC₅₀: 55.11 ± 4.62 µg/mL). Upon evaluation of the mechanism of action, the toxicity was mediated through an increased level of reactive radicals of oxygen and the subsequent release of cytochrome C, indicative of mitotoxicity. Hence, the D-Limonene rich essential oil of C. limetta is useful as a strong antibacterial and cytotoxic agent; the antioxidant properties exhibited also increase its utility value.

Chemical Composition and Biological Activities of the Leaf Essential Oils of Curcuma longa, Curcuma aromatica and Curcuma angustifolia

Curcuma species are widely used as a food additive and also in various medicinal purposes. The plant is a rich source of essential oil and is predominantly extracted from the rhizomes. On the other hand, the leaves of the plants are usually considered as an agrowaste. The valorization of these Curcuma leaf wastes into essential oils is becoming accepted globally. In the present study, we aim to extract essential oils from the leaves of Curcuma longa (LEO), C. aromatica (REO), and C. anguistifolia (NEO). The chemical composition of these essential oils was analyzed by GC-MS. Free radical scavenging properties were evaluated against the radical sources, including DPPH, ABTS, and hydrogen peroxide. The antibacterial activity was assessed by the disc diffusion method and Minimum inhibitory concentration analysis against Gram positive (Staphylococcus aureus) and Gram negative (Escherichia coli, Pseudomonas aeruginosa and Salmonella enterica) bacteria. Results identified the compounds α-phellandrene, 2-carene, and eucalyptol as predominant in LEO. The REO was predominated by camphor, 2-bornanone, and curdione. The main components detected in NEO were eucalyptol, curzerenone, α-lemenone, longiverbenone, and α-curcumene. Antioxidant properties were higher in the LEO with IC50 values of 8.62 ± 0.18, 9.21 ± 0.29, and 4.35 ± 0.16 µg/mL, against DPPH, ABTS, and hydrogen peroxide radicals. The cytotoxic activity was also evident against breast cancer cell lines MCF-7 and MDA-MB-231 cells; the LEO was found to be the most active against these two cell lines (IC50 values of 40.74 ± 2.19 and 45.17 ± 2.36 µg/mL). Likewise, the results indicated a higher antibacterial activity for Curcuma longa essential oil with respective IC50 values (20.6 ± 0.3, 22.2 ± 0.3, 20.4 ± 0.2, and 17.6 ± 0.2 mm). Hence, the present study confirms the possible utility of leaf agrowastes of different Curcuma spp. as a possible source of essential oils with pharmacological potential.

Characteristics of the leachate produced during nutrient recycling of food and poultry slaughter wastes by fly larvae

Biowaste management is a pertinent problem and nutrient recycling utilizing fly larvae is an emerging solution. The leachate produced during biowaste management has potential implications for the environment but studies on this issue are scanty. This study was conducted to assess the characteristics of leachate produced during the bioconversion of food (BW-I) and poultry slaughter waste (BW-II) by natural fly larval activity. The results showed that total volumes of 2.2 L and 1.1 L leachate were produced for BW-I and II respectively. The highest pH in BW-I leachate was 7.43 ± 0.01 and the lowest pH in BW-II was 3.30 ± 0.12. The highest levels of BOD in BW-I and II were 36733.33 ± 430.63 mg/l and 2800.000 ± 999.50 mg/l. The highest level of COD in BW-I was 52575.000 ± 1076.86mg/l while in BW-II it was 4316.67 ± 790.45 mg/l. The high BOD and COD values of the leachate indicated that they needed to be pretreated before being released into the environment.

First Report of Cylindrocladiella parva as a Grapevine Pathogen in New Zealand

Isolates morphologically identified as Cylindrocladiella parva were isolated from characteristic black foot symptoms on a grapevine (Vitis vinifera) rooted on 101-14 rootstock from Central Otago in 2005 and 101-14 rootstocks from a nursery in the Auckland Region in 2007 and 2008. On potato dextrose agar, the isolates initially produced cottony, white mycelia that turned grayish cream or golden cream within 10 days, the initially tawny colony undersides becoming dark brown with age. Conidia (0 to 1 septate; 16.4 to 17.0 [16.7] × 2.3 to 2.6 [2.5] μm) and abundant chlamydospores were produced. To confirm identity of the isolates, genomic DNA was extracted and the ribosomal DNA (rDNA) and β-tubulin gene were amplified and sequenced (3,4). Sequences of the PCR products were compared with sequences in GenBank. The rDNA (535 bp) and β-tubulin (297 bp) sequences of the four isolates were 100 and 99% identical, respectively, to reported sequences of C. parva in GenBank (AY793454, grapevine isolate (4)/AY793455 for rDNA; AY793486/AY793488, grapevine isolate (4)/AY793489/HM034822 for β-tubulin). Although C. parva was previously isolated from grapevines in New Zealand (2) and rootstocks of mature grapevines, cuttings, and graft unions of grafted young grapevines in South Africa (4), its role as a pathogen of Vitis spp. has not been confirmed (2,4). However, it has been reported as a pathogen of Eucalyptus spp. (1) and was also isolated from Telopea speciosissima and Macadamia integrifolia in New Zealand (2,4). The C. parva isolates were tested as a mixed inoculum (four isolates) for pathogenicity on roots of 10 grapevine rootstock plants each of cvs. 101-14 and Schwarzmann (Sch). The rootstocks were grown in potting mix for 4 months, after which the root systems of all vines were wounded with an asparagus knife with a sharp, square tip, driven vertically down into the soil at four equidistant locations approximately 8 cm from the trunk. Each plant was inoculated with 50 ml of the mixed-isolate conidial suspension (10⁶/ml), or 50 ml water (controls), followed by 50 ml of water. After 7 months of growth, the plants were harvested. For C. parva-inoculated plants, internal blackening of the stem base tissue was observed. Isolations from surface-sterilized trunk bases recovered C. parva from four and nine plants of 101-14 and Sch, respectively, with C. parva infections in 25 and 48%, respectively, of the four wood pieces taken per plant. Plants inoculated with water had no blackening and no C. parva was isolated from their stem bases. Mean shoot dry weights of inoculated plants (17.9 and 15.0 g for 101-14 and Sch, respectively) were significantly lower (P = 0.035) than noninoculated controls (26.5 and 20.0 g for 101-14 and Sch, respectively). Mean root dry weights were reduced by C. parva inoculation, although not significantly (32.7 and 27.0 g for C. parva inoculated 101-14 and Sch, respectively, and 36.2 and 27.4 g for control 101-14 and Sch, respectively). To our knowledge, this is the first report of C. parva as a pathogen of grapevines (2,4) and suggests that along with Cylindrocarpon spp., C. parva is part of the pathogen complex responsible for black foot of grapevines. References: (1) P. W. Crous et al. Plant Pathol. 42:302, 1993. (2) P. D. Gadgil et al. Fungi on Trees and Shrubs in New Zealand. Fungal Diversity Press, Hong Kong, 2005. (3) N. L. Glass and G. C. Donaldson. Appl. Environ. Microbiol. 61:1323, 1995. (4) G. J. van Coller et al. Australas. Plant Pathol. 34:489, 2005.