Guajava Research Articles

Evaluation of Antifungal Activity of Psidium guajava (Guava) Leaf Extracts

Aims: This study aimed to evaluate the effectiveness of four Psidium guajava leaf extracts against three strains of Candida albicans and a strain of Cryptococcus neoformans. Study Design: Experiment-observational study. Place and Duration of Study: P. guajava leaves were collected from specific areas in Regions Three and Four in Guyana; and the preparation of the leaf extracts and the treatment against the fungi were performed in two laboratories at the University of Guyana from August 2022-September 2023. Methodology: P. guajava leaves were washed with water, air-dried at room temperature, and ground in a disinfected food mixer. Extracts were prepared by soaking the ground leaves in different solvents, and then using the rotary evaporator to reduce the solutions and obtain crude extracts. Filter paper discs were prepared and allowed to soak in various concentrations of the crude extracts. The discs were then subjected to antifungal susceptibility testing on Potato Dextrose agar seeded with an appropriate fungus according to Clinical Laboratory Standards Institutes guidelines. The plates were incubated and the zone of inhibition (ZOIs) was measured. Results: P. guajava leaves were effective against all four strains of fungi evaluated. The largest ZOI was observed for C. neoformans (25 mm) with the ethyl acetate extract at 100 mg/mL concentration. Large ZOI was also observed for the three strains of C. albicans (10-15 mm). For one of the C. albicans strains, a ZOI significantly higher than the antifungal agents (ketoconazole and fluconazole) was observed with the P. guajava ethyl acetate extract at 100 mg/mL. Conclusion: It can be concluded that P. guajava leaves have antifungal activity against C. albicans and C. neoformans, potentially greater than current antifungal agents like ketoconazole and fluconazole.

Characterization of Copper Nanoparticles synthesized Using the Leaf Extracts of Lawsonia inermis, Eucalyptus globulus, Psidium guajava, and Azadirachta indica

Green synthesis of nanoparticles using plant extracts is a sustainable, eco-friendly, non-toxic, and cost-efficient approach. In this study, copper nanoparticles (CuNPs) were synthesized using the mehandi Lawsonia inermis, nilgiri Eucalyptus globulus, guava Psidium guajava, or neem Azadirachta indica leaf extracts and 1mM CuSO4.5H2O salt solution in a ratio of 1:3 at 800C temperature and characterized using UV-Visible spectroscopy, Fourier Transform Infrared spectroscopy, and Field Emission Scanning Electron Microscopy analysis. All the CuNPs showed colour change with characteristic surface plasmon resonance bands. The plasmon resonance bands of L. inermis, P. guajava, and A. indica CuNPs peaked at 300nm while those of E. globulus CuNPs peaked at 400nm. The CuNPs synthesized from L. inermis, E. globulus, and P. guajava leaf extracts exhibited brown colour while those synthesized from A. indica leaf extracts showed green colour. Eleven bands were present in L. inermis and A. indica CuNPs in the range of 538.61-3649.06cm-1 and 3867.26-519.02cm-1, respectively, while ten were in the E. globulus and P. guajava CuNPs in the range of 407.25-3326.78cm-1 and 3325.93-407.07cm-1, respectively. The L. inermis, E. globulus, and A. indica CuNPs were spherical, except P. guajava CuNPs which were flaky in shape. The particle size of L. inermis CuNPs was found in the range of 8.20 to 15.94nm; E. globulus CuNPs in the range of 7.52 to 67.47nm; P. guajava CuNPs in the range of 18.90 to 73.80nm and A. indica CuNPs in the range of 9.86 to 22.05nm.

Psidium guajava leaves extract alters colonic microbiome composition and reduces intestinal sodium absorption in rats exposed to a high-sodium diet

Abstract Objectives High sodium intake is a major risk factor for hypertension and renal diseases. Previous studies have shown that a suspension of ethanolic extract of Psidium guajava (guava) leaves (PsE) has antihypertensive effects in rats on a high-sodium diet (HSD), but some mechanisms to that remain unexplored. This study explored whether oral PsE treatment affects sodium handling by the intestine and alters the gut microbiome in HSD-fed rats. Methods Male Wistar rats were divided into two groups: standard salt diet (SSD) and HSD (0.9% Na+), from weaning. After 12 weeks, both groups received PsE (200 mg/kg) or a vehicle for an additional 4 weeks. Key findings Sodium excretion was measured using flame photometry, and sodium absorption was assessed by intestinal perfusion technique. The gut microbiome was analysed through 16S ribosomal gene sequencing. HSD increased faecal sodium, further elevated by PsE, which inhibited intestinal sodium absorption in HSD rats. HSD altered the abundance of specific bacterial families, which PsE partially reversed. No changes in alpha diversity were noted among groups. Conclusions These findings suggest that PsE inhibited intestinal sodium handling and that PsE, combined with increased faecal sodium, may reshape the gut microbiome of HSD rats to resemble that of SSD rats.

Characterization of the aroma and flavor profiles of guava fruit (Psidium guajava) during developing by HS-SPME-GC/MS and RNA sequencing

The flavor of guava, an important tropical fruit, is influenced by secondary metabolites. However, the mechanisms and processes underlying flavor formation in guava remain unclear. In this study, dynamic changes in volatile organic compounds (VOCs), sugars, and organic acids in guava peel and flesh across different developmental stages were investigated using headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC–MS) and high-performance liquid chromatography (HPLC). Here, we identified 90 VOCs, three sugars and eight organic acids. The dynamics of VOCs differ between the flesh and peel. The early developmental stages are more critical in influencing the variation of VOCs in the flesh, while VOC changes in peel occur more progressively across the developmental stages. By integrating transcriptomic and metabolomic analyses, we identified several key genes involved in VOC, sugar, and acid metabolism. This is the first study to describe the expression patterns of these genes throughout guava development, providing new insights into guava flavor development.

Evaluation of the Total Antioxidant Capacity of Three Selected Plants in Guyana

Aims: This study aimed to evaluate the leaf extracts of three commonly used medicinal plants in Guyana, namely Brassica juncea (mustard), Struchium sparganophora (antsbush), and Psidium guajava (guava), for their total antioxidant capacity. Study Design: Experimental-based study. Place and Duration of Study: The experiments were performed at the chemistry laboratory in the Faculty of Natural Sciences and the main laboratory in the College of Medical Sciences at the University of Guyana from September 2022 to August 2023. Methodology: The leaves of these plants were collected, washed, and air-dried at 280C for approximately one month, then pulverised in a sterilised food processor. Leaf extracts were then obtained by maceration with various solvents such as hexane, ethyl acetate, chloroform, and methanol; followed by filtration and rotary evaporation. The extracts obtained were then subjected to total antioxidant quantification via the phosphomolybdate method using a spectrophotometer. The total antioxidant capacity of the extracts was expressed as ascorbic acid equivalents. Results: Antioxidant activity was seen for all the extracts but in varying quantities. The highest antioxidant capacity was observed for the P. guajava extracts with a mean of 5.2 mg/mL. The least activity was observed for the S. sparganophora extracts, with a mean of 0.9 mg/mL. The ethanolic extracts showed the highest antioxidant capacity (10.6 mg/mL for P. guajava; 2.5 mg/mL for B. juncea). The hexane extracts had the least (0.33 mg/mL for P. guajava; 0.24 mg/mL for B. juncea). Conclusion: The leaves of B. juncea, S. sparganophora, and P. guajava have antioxidant capacity but those of P. guajava have greater potential for use as complementary and alternative treatments for chronic diseases.

Green synthesis of N-doped-carbon dots/ZnO for enhanced photocatalytic degradation of methylene blue dye: optimization of reaction parameters.

In this research work, nitrogen-doped carbon dots (N-CDs) adorned zinc oxide nanoparticles (N-CDs/ZnO) were successfully synthesized by a simple and cost-effective solution dispersion method and later on used as photocatalyst for decontamination of aqueous methylene blue (MB) dye on irradiation of UV light (300 W, 320-400nm) at room temperature. Both the N-CDs and ZnO were prepared through green technique utilizing non-toxic, inexpensive and eco-friendly precursors, namely Foeniculum vulgare and Psidium guajava leaf extract, respectively. All the synthesized samples exhibited crystalline nature with average diameter of particle 4.42nm, 12.38nm and 14.11nm corresponding to N-CDs, ZnO and N-CDs/ZnO, respectively. Further, band gap energy value (Eg) of 3.43, 2.76 and 2.49eV for N-CDs, ZnO and N-CDs/ZnO, respectively, were obtained by using Tauc's plot. The photocatalytic capability of the sample N-CDs/ZnO was compared with bare ZnO nanoparticles, utilizing identical experimental conditions. The results demonstrated that the composite exhibited notably higher photocatalytic degradation efficiency than bare ZnO nanoparticles up to 15.54%. Lower band gap value of N-CDs/ZnO was the major factor for exhibiting this behaviour, decreasing the recombination rate and thus enhancing the efficiency. Furthermore, N-CDs/ZnO exhibited 98.17% MB degradation under optimized conditions (0.03g, 5ppm, pH 10). The resultant N-CDs/ZnO exhibited good stability and decontamination efficiency up to five cycles with efficiency loss of only 7.89%. Along with, trapping experiments was conducted to analyze the role of active species involved for deep understanding of mechanism. The order of efficiency of active constituents was observed to be: •O2- > h+ > •OH. The study analyzed the non-toxic nature of treated water, revealing normal plant growth, suggesting its potential use in irrigation of parks and roadside areas. Overall, present research work obeys the green chemistry principles with the fabrication of highly efficient, eco-friendly, cost-effective photocatalyst N-CDs/ZnO by utilizing the green precursors for the whole research work.

Temporal dynamics of guava root-knot nematode under the effect of different management methods

Guava, Psidium guajava L., is one of the most produced fruit trees in tropical and subtropical regions but the presence of Meloidogyne enterelobii Yang & Eisenback (Order: Tylenchida, Family: Heteroderidae) in orchards reduces fruit productivity by up to 65%, justifying integrated management programs constantly searching for methods for its efficient and sustainable control. Thus, this study aimed to investigate the potential of chemical, biological, and resistance induction control methods to reduce the variables associated with M. enterelobii in guava orchards. This study was conducted in two areas with guava trees (cv. Paluma) naturally infested with M. enterelobii populations. Commercial doses of products based on Trichoderma harzianum (TRI), Ascophyllum nodosum+potassium hydroxide (EG), and fluensulfone (NI) were applied alone and in interactions in seven treatments+control. Soil and root samples from each treatment were collected monthly and the number of M. entorolobiieggs and individuals and normalized difference vegetation indices were quantified. Analyses conducted on R found that the joint use of TRI+EG reduced M. entorolobii by up to 50% at the soil level, further decreasing reproduction factors and that TRI obtained a 59% reduction at the soil level. Treatments with EG showed higher average productions. These results justify the importance of alternative methods and their possible association with chemicals to manage guava root-knot nematodes.

Impact of major homopteran pests on biochemical changes in guava (Psidium guajava L.) fruits and foliage

Impact of major homopteran pests on biochemical changes in guava (Psidium guajava L.) fruits and foliage

“Comparative evaluation of cytotoxicity of three herbal endodontic irrigants at three intervals of time” – An in vitro study

Aim: The aim of the study was to evaluate and compare the cytotoxicity of 25% of neem leaf extract (Azadirachta indica), 20% of guava leaf extracts (Psidium guajava), and 20% of cinnamon extract (Cinnamomum zeylanicum) irrigants at three intervals of time. Methodology: Four groups were formed (n = 15), Group 1 (control group) – normal saline solution, Group 2 – 25% of neem extract, Group 3 – 20% of guava extract, and Group 4 – 20% of cinnamon extract. Each group was further divided into three subgroups based on intervals (n = 5). Subgroup A – at 10 min, Subgroup B – at 20 min, and Subgroup C – at 30 min. One hundred microliters of each irrigant was added to 2 mL of the diluted red blood cells suspension obtained from a human volunteer. Hemoglobin (Hb) estimation was done with an automated hematology analyzer after incubating the test samples at 10, 20, and 30 min intervals. Results: The reduction in the mean Hb values was not statistically significant in the normal saline, guava, and cinnamon groups. However, in the neem extract group, the mean Hb values reduced significantly at P < 0.001. Among the subgroups, Subgroup A (10 min) showed the least cytotoxicity. Conclusion: In the present study, 20% guava extract had the lowest cytotoxicity and cytotoxicity increased with time. Hence, 20% guava extract can be used as an alternative to conventional irrigants as it has been shown to have the least cytotoxicity.

Evaluation of fermentative activities of yeasts isolated from guava fruit (Psidium guajava L.)

The study was conducted to isolate and screen yeast strains having good fermentative activities for wine production from guava (Psidium guajava L.). Yeasts were isolated from 22 samples of ripe guava fruits (including 4 varieties: Cattley, Taiwan, Ruby Supreme and Queen), which were collected from 6 provinces in the Mekong Delta. The yeast isolates were examined for biological characteristics, including colonial morphology and cell shape, after 48 h of culture, and investigated for fermentative characteristics including production of H2S gas, temperature and ethanol tolerance, ability to flocculate, production of extracellular enzymes, and fermentation of carbohydrate sources. The results showed that 33 yeast strains were isolated based on colony and cell morphologies. There were 9 isolates from the Taiwan variety, 13 isolates from the Queen variety, 7 isolates from the Cattley variety, and 4 isolates from Ruby supreme. Ten out of 33 isolates did not produce H₂S gas and had good flocculent ability in the fermentative solution after 7 days. Among them, the five yeast isolates (named NHCB1, NHCL4, NHCB4, DLCL1, and NHCB2) had good temperature tolerance at 39°C - 43°C, and high ethanol tolerance at 6% - 8% within 24 h. Three isolates (NHCL4, NHCB2, and NHCB4) with good ability to ferment glucose and fructose were selected for sequencing. The internal transcribed spacer sequences of all three strains were identical to those of Hanseniaspora opuntiae (> 99% identity). Briefly, this yeast strain can tolerate ethanol, ferment, and produce an appealing smell, bringing the potential for the production of wine or other fermented products.

Effect of Foliar Spray of Micro - Nutrients on Fruit Growth and Yield of Guava (Psidium guajava L.) cv. Lalit

Aim: To examine the effect of foliar spray of micro - nutrients on fruit growth and yield of guava (Psidium guajava L.) cv. Lalit. Study Design: The Randomized Block Design (RBD) experimental design was used. Place and Duration of Study: An experiment was carried out during Hasth Bahar flowering seasons of 2021-22 and 2022-23 at Horticulture Research Farm of Babasaheb Bhimrao Ambedkar University. Methodology: There were nineteen treatments with three replication. The variety selected for experiment was Lalit. Results: The foliar application of Borax 0.2%+Zinc 0.4% was found to be the best treatment in improving the morphological characteristics of guava such as fruit length (8.59 cm), fruit width (8.6cm), fruit volume (169.09 cm), fruit weight (174.99 g), peel weight (17.13g), pulp weight (155.32g),number of seed per fruit (212.49),seed weight per fruit (2.53g), seed weight kg per plant (1.23 kg), pulp and seed ratio (61.29) and specific gravity (1.03 g cc-1) of guava fruit. Conclusion: On the basis of the result obtained in the present investigation, it is concluded the combined foliar application of Borax 0.2%+Zinc 0.4% (T11). Therefore, combined spray Borax 0.2%+Zinc 0.4% (T11) can be advocated to guava growers for maximum growth and yield parameters of guava.

Fish oil-containing edible films with active film incorporated with extract of Psidium guajava leaves: preparation and characterization of double-layered edible film

The utilization of zein and gum arabic has grown in an attempt to formulate wall materials based on protein–polysaccharide complexes. This mixture provides a versatile delivery system for hydrophilic (guava leaf extract, GLE) or lipophilic (fish oil, FO) bioactive compounds, and it can be used as an edible film-forming polymer. This study was undertaken to characterize FO-containing edible films that were double-layered with a film containing GLE. Modified zein and gum arabic solutions (MG complex) were mixed at a ratio of 1:1.5 (v/v), adjusted to pH 5, added with glycerol (20% of the complex) and FO (5% of the complex), and finally adjusted to pH 5. This was prepared as the bottom/lower layer. The upper/active layer was prepared by mixing MG complex, glycerol, and GLE (1, 3, and 5% w/v of the complex). The total phenolic and flavonoid contents in GLE were 15.81 mg GAE/g extract and 6.99 mg QE/g extract, respectively. The IC50 of the DPPH radical scavenging activity of GLE was 26.86 ppm with antibacterial activity against Bacillus subtilis and Escherichia coli of 9.83 and 12.55 mm. The total plate counts of double-layered films containing GLE were retained below 3 log CFU/g during 28-day storage. The peroxide values of these films were dimmed for no more than 9.08 meq/kg sample on day 28 of storage. Thickness (872.00-971.67 μm), water vapor transmission rate (12.99-17.04 g/m2/day), tensile strength (1.56-2.02 kPa), elongation at break (61.53-75.41%), glass transition (52.74-57.50°C), melting peak (131.59-142.35°C), inhibition against B. subtilis (33.67-40.58 mm), and inhibition against E. coli (2.05-9.04 mm) were obtained by double-layered films. GLE can be successfully incorporated into the active layer of a double-layer film to improve its characteristics while significantly slowing down the microbial contamination and oxidation rate. MG complex and FO can also contribute to the performance of the edible film.

The Phytochemistry and Medicinal value of Psidium guajava ( guava ) : Antiobesity Effect

Obesity in society has reached epidemic proportions in the 21 st century. Being Overweight is not only appearance issue but also is actually a medical concern, because it is serious health condition. Diabetes and Heart diseases that can stem from obesity . The plant Psidium guajava Linn (Guava) is used not only as food but also as folk medicine. We subjected the leaves of these plant for Alcoholic extraction using solvent Ethanol and extract were prepared we infer that the oral administration of guava leaves extract shows Anti Obesity effect (weight loss). So this study proves that the guava leaves extract helps to control obesity.

Possibilities of competitive displacement of Bactrocera dorsalis (Hendel) by Bactrocera zonata (Saunders) (Tephritidae: Diptera) in guava Psidium guajava ecosystem in Sudan

Oriental fruit fly (OFF) Bactrocera dorsalis and peach fruit fly (PFF) Bactrocera zonata are the most notorious pests that invaded Sudan in 2005 and 2012, respectively, causing severe losses and hindering horticultural production and exports. Prior to 2012, OFF was the most abundant fly in guava orchards in Gezira State. Monitoring fruit flies to determine species composition, seasonality, and possibilities of competitive displacement was conducted in two guava (Psidium guajava) orchards in Gezira State; Fadasi and Gezirat Elfil, using food bait attractant and rearing flies from infested fruits..Longevity and survival percentages of developmental stages of the two species were also determined. Monitoring fly populations using Torula yeast and rearing of fruit flies from guava fruits revealed that OFF and PFF were the most prevalent species in guava ecosystem at both sites. At the Fadasi site, PFF was the predominant species representing (99.3%) of the guild of the trapped flies with an infestation level of 99.6%) flies/kg of guava fruits. At G. Elfil, OFF comprised 80.8% of the trapped flies with infestation level ca 53.6% while 19.2% of trapped flies were B. zonata with 46.4% infestation level. The high percentage of trapped OFF at G. Elfil might be attributed to multi-cropping system in the area. Developmental stages of PFF were shorter than that of OFF by 9.2 days, while its survival percentage was higher than that of OFF for all developmental stages. Competitive displacement of OFF by PFF in guava orchards at Fadasi site may have occurred as a result of the mono-cropping system, short developmental period, and high survival percentage of developmental stages of PFF on guava compared to that of OFF.

Influence of organic manures on yield parameters of guava (Psidium guajava) cv. Lucknow 49

The present investigation on “Influence of organic manures on yield parameters of guava (Psidium guajava) cv. Lucknow 49” was conducted in a farmer’s field located at Suthamalli village under Ariyalur District, Tamil Nadu during 2023-24. The study aimed to evaluate the application of organic manures, specifically combinations of farmyard manure, vermicompost, poultry manure, and neem cake significantly enhanced the yield parameters of guava cv. Lucknow 49 compared to untreated control conditions. The field experiment was laid out in randomized block design in three replications with fourteen treatments. The treatments were designed by combination of FYM, vermicompost, poultry manure and neem cake at different levels. The results of the present study indicated that the yield parameters viz., number of flowers/tree (162.16 and 173.36), number of fruits/tree (151.97 and 163.52), fruit set percentage (93.71 % and 94.32%), fruit length (6.71 and 6.98 cm), fruit diameter (6.89 and 7.10 cm), fruit weight (189.22 and 193.27 g) and yield/tree (29.83 and 34.18 kg) was found to be the highest in two successive crops, the treatment which received soil application of FYM 10 kg + vermicompost 5 kg + poultry manure 2.5 kg + neem cake 5 kg/tree followed by vermicompost 5 kg + poultry manure 2.5 kg + neem cake 5 kg/tree. The least values for all the yield parameters were noticed in the untreated control.

Antisalmonella Activities of Essential Oil of Psidium guajava Leaves: An In vitro and In vivo Study

Background: Life-threatening typhoidal salmonella infection is becoming more difficult to treat due to rising resistance to commonly used antibiotics. This resistance is aided by the biofilm-forming ability of the bacteria. This study investigated the in vitro and in vivo antisalmonella activities of essential oil of Psidium guajava leaves. Methods: Essential oil was extracted from the leaves of Psidium guajava with solvents. The sensitivity of Salmonella Typhi to the essential oil of Psidium guajava (EOPG) was assessed via the agar well diffusion method. Minimum inhibitory, bactericidal and biofilm-inhibitory concentrations (MIC, MBC and MBIC respectively) were measured using micro-broth dilution and crystal violet assay respectively. The effect of EOPG on the bacterial cell membrane was evaluated by measuring the efflux of potassium ions, inorganic phosphate and pyruvic acid. Bioautography and GC-MS were employed to identify the constituents of the active fraction of the EOPG. Effects of EOPG on the level of bacteremia and bone marrow infection in male Wistar rats were determined by plating caudal blood on salmonella-shigella agar. Selected serum cytokines were measured using ELISA kits. Effect on hepatic DNA was measured by comet assay while histological evaluation of the liver of infected rats was done by Hematoxylin and Eosin staining. Results: Essential oil of Psidium guajava leaves (EOPG) inhibited the growth of S. Typhi with a zone of inhibition of 13±0.2mm compared to 31±0.3mm recorded by ciprofloxacin. Minimum inhibitory, minimum bactericidal and minimum biofilm inhibitory concentrations were 25, >50 and 12.5 mg/mL respectively. Exposure to EOPG caused efflux of potassium ions, inorganic phosphate and pyruvic acid in S. Typhi. Oral administration of 50 mg/mL of EOPG reduced bacterial load in the blood and bone marrow of S. Typhi-infected rats significantly (P<0.05) when compared to untreated animals. Infection-induced reduction of serum IL-1β and rise in serum IFN-γ were ameliorated considerably in treated animals. The hepatic DNA of infected animals were protected from breakage in the group administered 50 mg/mL/day of EOPG compared with untreated, ciprofloxacin-treated as well as those administered 100 mg/mL/day of EOPG. Conclusion: EOPG has both in vitro and in vivo anti-salmonella activities, this could be exploited in developing new drug leads for treatment of typhoid fever

Isolation and Characterization of Stigmasterol from Psidium guajava Leaves: A Promising Bioactive Compound with Therapeutic Potential

This study aimed to isolate and characterize bioactive compounds from the leaves of Psidium guajava Linn. The hydroethanolic extract yielded 32% (80 g) from the crude material, which was subjected to column chromatography for fractionation. Structural elucidation of the isolated compound was performed using 1D and 2D Nuclear Magnetic Resonance (NMR) spectroscopy, including COSY, HSQC, and HMBC experiments. The spectral data confirmed the presence of stigmasterol, characterized by its distinct chemical shifts and long-range correlations between carbon and proton atoms. Stigmasterol was isolated as a white, crystalline solid and identified by its unique physio-chemical properties, such as solubility in organic solvents, a melting point of 163-164°C, and molecular formula C29H48O. This compound is known for its significant biological activities, including antibacterial, antimalarial, anti-inflammatory, antioxidant, and anticancer effects. By employing advanced techniques like 1D and 2D NMR spectroscopy, the study provides precise structural elucidation of stigmasterol, contributing to natural product research and reinforcing the medicinal potential of guava leaves as a source of pharmacologically active compounds. This adds to the existing knowledge of the plant’s bioactive components and their applications in medicinal chemistry

Chitosan xerogel embedded with green synthesized cerium oxide nanoparticle: An effective controlled release fertilizer for improved cabbage growth

With the growing awareness on the adverse effects of conventional fertilizers; the use of sustainable and controlled release fertilizers has garnered much significance. In the present study, we report the synthesis of chitosan-benzaldehyde Schiff base xerogel incorporated with green synthesized cerium oxide nanoparticle using Psidium guajava leaves extract as a sustainable fertilizer. Spherical CeO2 NPs having an average particle size of 15.3 nm and zeta potential of – 39.9 mV was obtained. The urea-loaded nanocomposite xerogel (CsB@U/CeO2) was examined for cabbage growth. The water retention capacity extended for >2 weeks. A controlled release profile for urea was accomplished from CsB@U/CeO2 for a period extending for 30 days. The kinetics assay suggested that presence of CeO2 NPs asserted a greater role in urea-controlled release from the CsB@U/CeO2 nanocomposite hydrogel owing to polymer relaxation. The growth parameters of cabbages such as head height, diameter, fresh head weight, head circumference was enhanced in plants fertilized by CsB@U/CeO2 as compared to urea. Furthermore, the phenolic content, free radical scavenging activity, protein content, sugar and flavonoid content were also found higher in CsB@U/CeO2 fertilized plants. This study puts forth CsB@U/CeO2 xerogel can be potentially harnessed as an alternative to urea in sustainable agriculture.

Combined effects of deficit irrigation and mulching on fruit quality and bioactive compounds of VNR Bihi guava (Psidium guajava)

The present study was carried out during 2019–20 and 2020–21 at Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, Uttarakhand to assess the combined effects of deficit irrigation and mulching on a 5-year- old VNR Bihi guava (Psidium guajava L.) orchard. The experiment consisted of three irrigation regimes, viz. deficit irrigation at 50% ETc (DI50); deficit irrigation at 75% ETc (DI75); and full irrigation at 100% ETc (FI100); and four mulching treatments, viz. silver-black mulch (MSB); black mulch (MB); organic mulch (MOM); and without mulch (MWM) laid out in a factorial randomised block design (F-RBD) with three replications. Results showed that fruit number and yield/tree were recorded highest in trees irrigated with DI75 and mulched with silver-black mulch. Under treatment DI50 fruit had the highest concentration of soluble solids, with Brix levels of 12.35°B and 12.78 °B during the years 2019–20 and 2020–21, respectively. Total sugars content was significantly increased under DI50 by 7.73 and 7.36%, respectively as compared to FI100 during both the years of experimentation. The biochemical properties such as total phenolics, total flavonoids and antioxidant (DPPH) activity also increased as irrigation regimes decreased from FI100 to DI50. The total phenolic and flavonoids content were improved by 19.19 and 33.44%, respectively under DI50 when compared to FI100. Significant differences among different mulch treatments with respect to quality parameters were also observed except DPPH activity. Silver-black mulch followed by black mulch resulted in higher soluble solids content, total sugars, ascorbic acid, total phenolic content, total flavonoids and DPPH activity. These findings demonstrate the positive effect of water deficit practice on bioactive compounds and the appropriateness of deficit irrigation and mulching as irrigation management strategies in the fruit orchards that improve fruit commercial value and conserve water.

Isolation of saponins from the leaves of Psidium guajava and Garcinia quaesita and antioxidative capacities

Isolation of saponins from the leaves of Psidium guajava and Garcinia quaesita and antioxidative capacities