Paper Example on Herbal Plants: Natural Sources of Safer Therapeutic Treatments

Introduction

For many centuries, curative plants have been used as curative drugs in different indigenous systems of medicines and have long been viewed as a source of curative remedy based on the cultural and religious traditions. Plant-based functional foods have over the years gained popularity due to their safer therapeutic applications confirmed from uncountable number of evidences and researches. The safer therapeutic applications of the herbal plants is linked to the rich phytochemistry that these plants possess

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Herbal medicines are considered safe compared to the modern allopathic medicines and use of these herbal plants in developing nations turned out to be World Health Organization policy from the year 1970 (Perveen 1). Out of the approved 520 new drugs between 1983-1994 by US Food or Drug Administration, at least 30 drugs were derived directly from natural products sources with 173 synthetic or semi-synthetic. Among the many medicinal plants used for medical purposes is the Black seed (Nigella sativa). Nigella Sativa is a yearly flowering plant from Ranunculaceae family which is inherent to Southwest Asia. It is widely used across the world and very prevalent in innumerable traditional settings of medicines like Sidda and Ayurveda , and Tibb and Unani (Ahmad, et al 1). The plant is highly valued in the Islamic religion and according to the Islamic prophet Muhammad, the black seed can easily all diseases except death (Kamil 1). The seed has medicinal uses especially in the treatment of diabetes, asthma, arthritis. Digestive diseases, and inflammatory diseases. For the longest time, the use of plants for medicinal purposes has been recognized since the traditional times and still in the recent times, there has been a notable rise in the use of medicinal plants as compared to the chemical drugs (Kooti, et al 2). It has been recently estimated that by the World Health Organization that at least 80% of people derive medicinal benefits from herbs (Kooti et al 2). Nigella Sativa has been shown to have a wide range of activities such as diuretic immunomodulatory, analgesic, gastroprotective, renal antioxidant, hepatoprotective, anti-inflammatory and spasmolytic (Begum and Mannan 2). Out of the many herbs subjected to research, black seeds are one of them with a rich cultural and historical heritage in the middle east and South Asia where the seed is commonly used to promote health and fight diseases. Due to its incredible power of healing and accreditation from wide number of studies by researchers, Nigella Sativa has been recognized among the top-ranked effective and evidence-based herbal medicines. The herb contains a major bioactive component of the essential oil known as thymoquinone (TQ) which reveals most of the herb’s therapeutic properties (Ragheb 1). This paper will focus on Pharmacological characteristics, biodiversity, safety and toxicity of Nigella Sativa. Further, it will discuss the clinical trials and effects of Nigella Sativa on biological systems.

Pharmacognostical Characteristics of Nigella Sativa

Nigella sativa is an annual herb that grows about 45 cm by height while leaves are from 2.5-5.0 cm long.

Morphology of the Plant

The plant of Nigella sativa grows from 20-90 cm tall and has finely divided leaves with narrowly linear to threadlike leaf segments (Petruzzello, n.d). The branched stems of the black cumin plants bear fine deeply divided leaves and has a developed taproot. The plant possesses subtle flowers with white, yellow, pale blue, pink, and pale purple colors. Each flower of the Nigella sativa has at least 5-10 petals while its fruit is a big and inflated which contains 3-7 united follicles, each encompassing a number of seeds. Its black triangular or rather pyramidal seeds are borne in a capsule with from 5-6 segments each of which terminates in an elongated projection. Nigella sativa plant can grow I a number of soils, can readily reseed and also become weedy in some areas.

Seeds and Powder Characteristics

Microscopically, the crosswise section of seed shows single-layered epidermis which comprises of elliptical thick-walled cells. It is also covered outwardly by a papillose cuticle and filled with dark brown contents. The epidermis of the seed is then covered by the is followed by a 2-4 layers of thick-walled, rectangular elongated cells with the inner pigment layer composed of thick-walled rectangular elongated or nearly columnar cells. The black seed’s endosperm consists of thin-walled and polygonal cells filled with air globules. The powder microscopy of black seed powder demonstrates brownish black parenchymatous and oil globules. Macroscopically, the seeds of the Nigella Sativa are small dicotyledonous, angular, trigonus, regulose-tubercular, 2-3.5mm *1-2mm, white inside and black externally with a slightly aromatic odor and bitter taste.

Bioavailability, Safety, and Toxicity of Nigella Sativa

Bioavailability

Bioavailability is the extent a drug or substance becomes completely available to the intended biotic destination (Price & Deven 1). More accurately, bioavailability is a measure of the rate and fraction of the preliminary dose of a drug that successfully reaches either the biological destination or the body fluid realm from which the drug’s intended targets have unconstrained access. However, considering majority purposes bioavailability is basically the fraction of the active drug which enters the systemic circulation and successfully reaches the biological destination. In pharmacokinetics, bioavailability is a very essential part and the intravenous bioavailability of a drug is continuously 100 percent with the oral bioavailability normally less than 100 percent due to fast-pass elimination and incomplete absorption (Si mui sim 15). The dose and the route of administration (ROA) of a drug has a noteworthy impact on the extent and rate of bioavailability such that the dose of the drug administered is supposed to be indirectly proportional to its bioavailability and thus, for every drug with relatively lower bioavailability , a larger dose is needed in order to breach the smallest effective concentration threshold. For the ROA, altering route of administration results to alteration n of the dosage such that if an oral drug needs passage through the gastrointestinal (GI) system could then make it subject to intestinal absorption and hepatic first pass metabolism.

Considering the black cumin (Nigella sativa), thymoquinone (TQ) obtained from the seed is usually a natural product with anti-inflammatory, ant-oxidant, an hepatoprotective effects but unfortunately registers poor bioavailability (Elmowafy, et al 13). Thymoquinone which is chemically referred to as 2-isopropyl-5-methyl-1,4-benzoquinone possess a molecular weight of 164g/mol and has a key phytochemical bioactive ingredient in the nigella sativa oil and extracts.

Safety

Clinical Trials

Recently reviewed preclinical studies reported that nigella sativa has broad and crucial pharmacological actions .Review of clinical trials by Tavakolli et al (4) showed that nigella sativa possesses important and crucial effects for the treatment of patients with a number of diseases such as auto-immune disorders, inflammatory and metabolic syndrome. Anti-epileptic, anti-microbial, and anti-nociceptive properties of the black cumin seed were acknowledged. The mode of action of nigella sativa is suggested to be mediated by anti-oxidant cyptoprotective, immunomodulating, and inhibitory effects on mediators of inflammation (Dajani et al 4). However, side effects of the herbal drug were also recognized although they appeared not to be serious.

Clinical Trials on Nigella Sativa Safety

To assess the safety of nigella sativa as an herbal drug, administration of NS oil (5 ml/day) to volunteers who were healthy was performed for 8 weeks and reported to have any noteworthy kidney, gastrointestinal, and liver side effects. Another clinical trial was performed on a total of 39 centrally obese men showed that intake of NS seeds (3 g/day for 3 months only) possessed no detectable side effects. Qidwai and Ashfaq (10) stated that the administration of NS seeds (2 g/day for a period of 6 weeks) did not in any way affect the Serum Creatinine (Cr) or serum alanine amino transferase (ALT) levels in the adults. Furthermore, doses of 1, 2, and 3 g/day of nigella sativa for a period of 3 months did not unpleasantly or significantly affect the hepatic or renal function so the patients suffering from diabetes. Nigella sativa powder intake for 40 days also revealed more significant change in the in the total leukocyte or platelet hence safe for use.

Another clinical trial carried was use of nigella sativa tea (5 g/day) added to the usual oral anti-diabetic, exercise and diet drugs for a period of 6 months. It demonstrated noteworthy decreases in aspartate aminotransferase (AST), serum total, ALT, serum Cr, direct and indirect bilirubin, levels of blood urea in type 2 Diabetes patients as well as notable and improved kidney and liver functions. Moreover, Nigella sativa intake (400 or 200 mg/day) for a period of 2 moths was stated to cause no observable or notable complications in mild hypertension patients.

Nigella sativa oil intake which was equal to oil obtained from 0.7 g of seeds was practiced for a maximum, of 40 days and the results indicated that there was a realistic liver and kidney safety in the type 2 diabetes mellitus patients and the intake of the Nigella sativa oil did not in any way interfere with the total leukocyte or platelet count. Another clinical trial aimed to determine the side effects or rather safety of nigella sativa as an anti-cancer agent in children. Children aged 2-18 years suffering from acute lymphoblastic leukemia given nigella sativa powder (40 mg/kg in 2 equal doses for a period of 3 months), along with conventional therapy had less side effects compared to those that had L- asparaginase and conventional therapy where conventional therapy involves vincristine, daunorubicin, and prednisolone (Dogar et al 12). This clinical evidence demonstrates that nigella sativa powder as an anti-cancer agent is a very important and key substitute for L-asparaginase in the treatment of patient with acute lymphoblastic leukemia (ALL).

A clinical trial on the safety of nigella sativa intake in seasonal allergic rhinitis patients was carried out. The patients were expected to take 250 mg/day for a period of two weeks and eventually reported no adverse effects. Still, it was confirmed that when patients suffering from the seasonal allergic rhinitis patients were treated using nigella sativa oil nasal drops, nasal dryness was noted (Alsamarai et al 7).

Application of nigella sativa oil was done to patients suffering from vitiligo twice a day for a period of 6 months. Nigella sativa intake (0.5 ml/kg/day) in osteopenic postmenopausal women for three months demonstrated no beneficial effects although there were no notable adverse side effects demonstrated. Another clinical trial was conducted on Iranian infertile men to assess the effects and safety level of nigella sativa. nigella sativa was taken (5 ml/day) on abnormal semen quality of the infertile men and there were no observable side effects. However, to functional dyspeptic patients, mild and adverse side effects were noticed such as bloating, nausea, and burning sensation, On the contrary, some cases of hypoglycemia and epigastric pain were testified as adverse effects when the nigella sativa capsules were used to treat patients suffering from hepatitis C virus (HCV). Dirjomuljono et al (8) validates the safety of Nigella sativa extract (1080 mg/per day) when used to treat the patients suffering from tonsillopharyngitis. Another clinical trial that was used to investigate the anti-cestodal effects o...