Monascus species have been used for the production of many industrially and medically important metabolites, most of which are polyketides produced by the action of polyketide synthases that use acetyl-CoA and malonyl-CoA as precursors, and some of them are derived from acetate. In this study the effects of acetic acid, and two kinds of acetates, sodium acetate and ammonium acetate at different concentrations (0.1%, 0.25% and 0.5%) on the morphologies, biomasses, and six major Monascus pigments (MPs) of M. ruber M7 were investigated when M7 strain was cultured on potato dextrose agar (PDA) at 28 °C for 4, 8, 12 days. The results showed that all of the added acetate species significantly affected eight above-mentioned parameters. In regard to morphologies, generally the colonies transformed from a big orange fleecy ones to a small compact reddish ones, or a tightly-packed orange ones without dispersed mycelia with the increase of additives concentration. About the biomass, addition of ammonium acetate at 0.1% increased the biomass of M. ruber M7. With respect to six MPs, all acetate species can enhance pigment production, and ammonium acetate has the most significant impacts. Production of monascin and ankaflavin had the highest increase of 11.7-fold and 14.2-fold in extracellular contents at the 8th day when 0.1% ammonium acetate was supplemented into PDA. Intracellular rubropunctatin and monascorubrin contents gained 9.6 and 6.46-fold at the 8th day, when 0.1% ammonium acetate was added into PDA. And the extracellular contents of rubropunctamine and monascorubramine were raised by 1865 and 4100-fold at the 4th day when M7 grew on PDA with 0.5% ammonium acetate.

ObjectivesConsidering the therapeutic potential of honey and Nigella sativa (HNS) in coronavirus disease 2019 (COVID-19) patients, the objective of the study is defined to evaluate the prophylactic role of HNS. Trial designThe study is a randomized, placebo-controlled, adaptive clinical trial with parallel group design, superiority framework with an allocation ratio of 1:1 among experimental (HNS) and placebo group. An interim analysis will be done when half of the patients have been recruited to evaluate the need to adapt sample size, efficacy, and futility of the trial.ParticipantsAll asymptomatic patients with hospital or community based COVID-19 exposure will be screened if they have had 4 days exposure to a confirmed case. Non-pregnant adults with significant exposure level will be enrolled in the study● High-risk exposure (<6 feet distance for >10min without face protection) ● Moderate exposure (<6 feet distance for >10min with face protection)Subjects with acute or chronic infection, COVID-19 vaccinated, and allergy to HNS will be excluded from the study.Recruitment will be done at Shaikh Zayed Post-Graduate Medical Institute, Ali Clinic and Doctors Lounge in Lahore (Pakistan). Intervention and comparatorIn this clinical study, patients will receive either raw natural honey (0.5 g) and encapsulated organic Nigella sativa seeds (40 mg) per kg body weight per day or empty capsule with and 30 ml of 5% dextrose water as a placebo for 14 days. Both the natural products will be certified for standardization by Government College University (Botany department). Furthermore, each patient will be given standard care therapy according to version 3.0 of the COVID-19 clinical management guidelines by the Ministry of National Health Services of Pakistan.Main outcomesPrimary outcome will be Incidence of COVID-19 cases within 14 days of randomisation. Secondary endpoints include incidence of COVID-19-related symptoms, hospitalizations, and deaths along with the severity of COVID-19-related symptoms till 14th day of randomization. RandomisationParticipants will be randomized into experimental and control groups (1:1 allocation ratio) via the lottery method. There will be stratification based on high risk and moderate risk exposure. Blinding (masking)Quadruple blinding will be ensured for the participants, care providers and outcome accessors. Data analysts will also be blinded to avoid conflict of interest. Site principal investigator will be responsible for ensuring masking.Numbers to be randomised (sample size)1000 participants will be enrolled in the study with 1:1 allocation.Trial StatusThe final protocol version 1.4 was approved by institutional review board of Shaikh Zayed Post-Graduate Medical Complex on February 15, 2021. The trial recruitment was started on March 05, 2021, with a trial completion date of February 15, 2022. Trial registrationClinical trial was registered on February 23, 2021, www.clinicaltrials.gov with registration ID NCT04767087.