Morus alba (Moraceae) – White mulberry

Morus alba, is a deciduous tree of the family Moraceae, native to East Asia and especially China, from where it has spread widely to Europe and many other temperate and subtropical regions. It is a fast-growing, relatively long-lived tree which, under favourable conditions, can reach 10–15 metres or more in height, with an irregularly branched trunk and a dense, broad, rounded crown. The root system is robust and deep, with extensive lateral branching, a feature that favours soil stabilisation but makes the species somewhat sensitive to excessively dry soils if not adequately watered.

The leaves, deciduous and alternate, are markedly polymorphic: they may be ovate-acute, sometimes cordate, entire or three-lobed, especially on vigorous suckers. The margin is serrated, the apex acute and the base slightly cordate. The upper surface is usually glabrous and glossy light green in spring and summer, turning bright yellow in autumn, while the lower surface is paler and may be slightly pubescent along the veins. Rich in chlorenchyma, the leaves represent the principal food source for the silkworm (Bombyx mori), a role that has been crucial in the development of sericulture and the historical mulberry–silkworm farming system, with profound economic and cultural impact from Asia to the Mediterranean.

The flowers of Morus alba are small, inconspicuous and grouped in distinct male and female catkins, reflecting the variable sexual systems of the species (monoecious, dioecious or polygamous depending on population and clone). After pollination, the plant produces characteristic fleshy pseudofruits, which are in fact infructescences known botanically as soroses: aggregates of small druplets fused together into an elongated, soft, juicy structure. The colour ranges from white-cream to pink and sometimes darker shades in selected forms. The ripe fruits are edible, with a sweet, delicate flavour, and are eaten fresh or processed into juices, jams and other products, although their high perishability and delicate texture limit large-scale commercial distribution compared with other fruits.

From an ecological standpoint, white mulberry is a heliophilous species that prefers sunny or semi-shaded sites and well-drained soils, from moderately acidic to slightly alkaline. It is often used as a pioneer tree in traditional agro-forestry systems, planted in rows, shelterbelts and field margins, where it provides shade, wind protection and organic matter. Its considerable ecological plasticity has favoured naturalisation in many extra-Asian regions. The fruits constitute a food source for birds and small mammals, which ensure zoochorous seed dispersal, while the dense crown offers refuge and nesting sites for various organisms.

On the chemical–nutritional and phytochemical level, Morus alba is rich in secondary metabolites distributed throughout the plant. The fruits contain simple sugars, organic acids, vitamin C, dietary fibre and a polyphenolic profile that includes anthocyanins (more abundant in dark-fruited forms), flavonols and phenolic acids, which contribute to their antioxidant activity. The leaves are particularly noteworthy for their content of flavonoids, simple phenols, phytosterols and, above all, the iminosugar alkaloid 1-deoxynojirimycin (DNJ), a potent α-glucosidase inhibitor. DNJ and related compounds have attracted considerable attention for their potential hypoglycaemic effects, especially in the context of type 2 diabetes, by modulating postprandial glucose absorption.

A growing body of experimental and clinical research indicates that extracts of mulberry leaves may exert antidiabetic, antioxidant, anti-inflammatory, hypolipidaemic and more generally cardiometabolic-supporting effects. In animal models and early clinical trials, leaf preparations have been associated with improvements in blood glucose control, lipid profile, and oxidative stress markers, supporting their traditional use as complements to standard therapy in metabolic disorders, particularly in parts of Asia where mulberry leaf teas and extracts are widely consumed. Nevertheless, full elucidation of mechanisms, optimal dosing, long-term safety and drug–herb interactions remains an active area of research, and leaf extracts should not be regarded as substitutes for evidence-based medical treatment of diabetes or other chronic diseases.

From the perspective of everyday diet, moderate consumption of fresh fruits and leaf-based preparations (such as mulberry leaf teas) can reasonably be integrated into a balanced dietary pattern, where they may contribute micronutrients and bioactive compounds. The situation is different for high-dose supplements or concentrated extracts, in which the levels of DNJ and other constituents are greatly increased: in such cases, careful evaluation of standardisation, duration of use and potential adverse effects is essential, particularly for individuals already receiving pharmacological treatment for diabetes, dyslipidaemia or other chronic conditions.

Historically and culturally, white mulberry is inseparable from the development of silkworm rearing and the silk trade routes, serving as the botanical foundation of an agro-industrial system that linked agriculture, craftsmanship and long-distance commerce over many centuries. In European rural landscapes, especially in Italy and other Mediterranean countries, rows of mulberry trees were once a familiar feature, providing leaves for silkworms, fruit for human and animal consumption, shade, wind protection and landscape value. Today, interest in Morus alba is being renewed thanks to its nutritional value, phytotherapeutic potential and its role in more sustainable agro-food chains, including integrated systems that combine leaf production, fruit harvesting and environmental services such as erosion control and biodiversity support.

Botanical classification (APG IV system)

Indicative nutritional values per 100 g (fresh fruits of Morus alba)
Values refer to fresh white mulberries; they may vary with cultivar, ripeness and growing conditions.

At typical serving sizes (around 40–80 g of fresh fruits), white mulberries provide a low–moderate energy intake, almost entirely from carbohydrates, together with vitamin C, a modest amount of dietary fiber, and small quantities of minerals.

Lipid profile note

Fresh white mulberries have a very low fat content. Saturated fatty acids (SFA) are present only in trace amounts; when SFA dominate over unsaturated fats in the overall diet, they are generally considered less favourable for cardiovascular health. The small lipid fraction contains very small amounts of MUFA and PUFA, which are usually regarded as more favourable when they replace part of dietary SFA. In the case of Morus alba, however, the absolute fat intake from typical portions is so low that its impact on total dietary fat balance is negligible.

Plant Characteristics:
Morus alba is a deciduous tree that can grow up to 10-15 meters in height. It has a broad, spreading canopy with large, ovate leaves that can be smooth or lobed. The tree produces small, inconspicuous flowers, and the fruit is a multiple fruit composed of small drupelets. The berries transition from white to pink to dark purple as they ripen and are known for their sweet, juicy flavor.

Chemical Composition and Structure:
The white mulberry fruit and leaves contain a range of beneficial compounds:

Vitamins: High in Vitamin C and some B vitamins.

Minerals: Contains potassium, calcium, magnesium, and iron.

Antioxidants: Rich in anthocyanins, flavonoids, and polyphenols, which contribute to its antioxidant properties.

Dietary Fiber: High in fiber, supporting digestive health.

Organic Acids: Includes various organic acids that contribute to its health benefits.

How to Cultivate It:

• Climate: Prefers temperate and subtropical climates. It thrives in regions with mild winters and warm summers.
• Soil: Grows well in well-drained, loamy soils with a slightly acidic to neutral pH.
• Sunlight: Requires full sun to partial shade for optimal growth and fruit production.
• Watering: Needs regular watering, particularly during dry periods. Ensure good drainage to prevent root rot.
• Pruning: Regular pruning is necessary to maintain the tree’s shape, remove dead or diseased wood, and promote healthy growth.

Uses and Benefits:

• Culinary Uses: The fruit can be consumed fresh or dried and is used in jams, juices, and desserts. The leaves are used in traditional dishes.
• Medicinal Uses: In traditional medicine, the leaves are used to manage blood sugar levels, support cardiovascular health, and improve overall wellness. The fruit has anti-inflammatory and antioxidant properties.
• Economic Uses: The leaves are crucial for silk production, providing food for silkworms.

Cosmetic Uses:

• Antioxidants: The fruit and leaf extracts have powerful antioxidant properties that help protect the skin from damage caused by free radicals, reducing signs of aging.
• Skin Lightening: White mulberry extracts are known for their skin-lightening effects, helping to even out skin tone and reduce dark spots and discolorations.
• Hydration: The nutrients in the fruit and leaves help keep the skin hydrated and soft.
• Anti-inflammatory: The extracts have anti-inflammatory properties that can soothe irritated skin, reduce redness, and calm inflammation.
• Collagen Production: Antioxidants and vitamins in the extracts may boost collagen production, enhancing skin elasticity and reducing wrinkles.

           Applications:

• Skincare Products: Used in creams, lotions, serums, and masks to improve skin hydration, reduce pigmentation, and provide anti-aging benefits.
• Anti-aging Treatments: Incorporated into products aimed at reducing wrinkles and improving skin texture.
• Brightening Products: Used in formulations designed to lighten skin tone and address uneven pigmentation.

INCI Functions:

Skin conditioning agent. It is the mainstay of topical skin treatment as it has the function of restoring, increasing or improving skin tolerance to external factors, including melanocyte tolerance. The most important function of the conditioning agent is to prevent skin dehydration, but the subject is rather complex and involves emollients and humectants that can be added in the formulation.

Antifoaming agent. The constituent factors for foam stabilisation are the concentration of nanoparticles and hydrophobicity. Foam, even when used in separation operations such as fractionation or flotation, can cause a decrease in density and a deterioration in quality in cosmetic products.  The defoaming agent (non-polar oil, silicone oils, hydrophobic solid particles or mixtures of both) is strongly influenced by viscosity and, to an almost directly proportional extent, concentration. However, defoamers can carry an irreversible source of contamination.

Cosmetic astringent. This ingredient exerts a direct effect on the skin by tightening dilated pores by contracting stratum corneum cells and removing superfluous oil.

Humectant. Hygroscopic compound used to minimise water loss in the skin and to prevent it from drying out by facilitating faster and greater absorption of water into the stratum corneum of the epidermis.  The epidermis is the most superficial of the three layers that make up human skin (epidermis, dermis and hypodermis) and is the layer that maintains hydration in all three layers. In turn, the epidermis is composed of five layers: horny, the most superficial, granular, spinous, shiny, and basal. Humectants have the ability to retain the water they attract from the air in the stratum corneum and have the function of moisturising the skin. They are best used before emollients, which are oil-based.

Environmental and Safety Considerations:

• Pests and Diseases: Susceptible to pests like scale insects and diseases such as powdery mildew. Regular monitoring and management are required.
• Invasive Potential: Generally not considered invasive but can spread rapidly in favorable conditions.
• Safety: Generally regarded as safe for topical application. However, like all extracts, it should be used in accordance with established guidelines to avoid potential allergic reactions or skin irritations. 

References__________________________________________________________________________

(1) Yuan Q, Zhao L. The Mulberry (Morus alba L.) Fruit-A Review of Characteristic Components and Health Benefits. J Agric Food Chem. 2017 Dec 6;65(48):10383-10394. doi: 10.1021/acs.jafc.7b03614. Epub 2017 Nov 20. PMID: 29129054.

Abstract. Mulberry (Morus alba L.) fruit has a high yield in one fruiting season in many countries, especially in Asia, and a long history of use as an edible fruit and traditional medicine. A great diversity of nutritive compounds such as fatty acids, amino acids, vitamins, minerals, and bioactive compounds, including anthocyanins, rutin, quercetin, chlorogenic acid, and polysaccharides have been found in mulberry fruit depending on the cultivars and maturity stages. Furthermore, the extracts and active components of mulberry fruit have demonstrated numerous biological activities, including antioxidant, neuroprotective, antiatherosclerosis, immunomodulative, antitumor, antihyperglycemic, and hypolipidemic activities in in vitro and in vivo studies, and they have received increasing interest from researchers and pharmaceutical companies. Although some mechanistic studies further substantiate these potential health benefits of mulberry fruit, a need exists to make a better understanding of the roles of these compounds in traditional medicine and the diet. This review provides recent findings regarding the chemical constituents and biological activities of mulberry fruit, which may be useful for stimulating deep research of mulberry fruit and for predicting their uses as important and safe contributors to benefit human health.

Zhang H, Ma ZF, Luo X, Li X. Effects of Mulberry Fruit (Morus alba L.) Consumption on Health Outcomes: A Mini-Review. Antioxidants (Basel). 2018 May 21;7(5):69. doi: 10.3390/antiox7050069. 

Abstract. Mulberry (Morus alba L.) belongs to the Moraceae family and is widely planted in Asia. Mulberry fruits are generally consumed as fresh fruits, jams and juices. They contain considerable amounts of biologically active ingredients that might be associated with some potential pharmacological activities that are beneficial for health. Therefore, they have been traditionally used in traditional medicine. Studies have reported that the presence of bioactive components in mulberry fruits, including alkaloids and flavonoid, are associated with bioactivities such as antioxidant. One of the most important compounds in mulberry fruits is anthocyanins which are water-soluble bioactive ingredients of the polyphenol class. Studies have shown that mulberry fruits possess several potential pharmacological health benefits including anti-cholesterol, anti-obesity and hepatoprotective effects which might be associated with the presence of some of these bioactive compounds. However, human intervention studies on the pharmacological activities of mulberry fruits are limited. Therefore, future studies should explore the effect of mulberry fruit consumption on human health and elucidate the detailed compounds. This paper provides an overview of the pharmacological activities of mulberry fruits.

(2) Kwon RH, Thaku N, Timalsina B, Park SE, Choi JS, Jung HA. Inhibition Mechanism of Components Isolated from Morus alba Branches on Diabetes and Diabetic Complications via Experimental and Molecular Docking Analyses. Antioxidants (Basel). 2022 Feb 14;11(2):383. doi: 10.3390/antiox11020383.

Abstract. Previously, we reported the anti-diabetic effect of Morus alba root bark and the compounds therein. In our continuous study of other parts of this plant, the ability of the branch of Morus alba to inhibit α-glucosidase, protein tyrosine phosphatase 1B (PTP1B), and advanced glycation end products (AGEs) formation was evaluated. Moreover, there are no previous studies that have performed enzyme kinetics and molecular docking analyses, along with assessments of peroxynitrite (ONOO-) inhibitory activities. Since the Morus alba branch exhibited favorable inhibitory effects, repeated column chromatography was performed to obtain eight compounds, including four flavonoids (1, 3, 6, 8), one arylbenzofuran (2), one stilbene (5), one Diels-Alder-type adduct (7), and one sterol (4). Among them, compounds 1-3 and 5-7 were mixed-type inhibitors of α-glucosidase, sharing the same catalytic residues with acarbose and the same allosteric sites with (Z)-3-bytylidenephthalide. On the other hand, kuwanon C (1) and oxyresveratrol (5) interacted with residues of the allosteric site (α3 and α6 helices) of PTP1B, indicating their use as non-competitive inhibitors. Interestingly, kuwanon G (7) directly bound the catalytic site, or interrupted the binding between the substrate and the active site, as a mixed-type inhibitor. Moreover, most of the compounds exhibited greater activity against AGE formation and ONOO- than positive controls. The IC50 values required to inhibit ONOO- using compounds 1, 3, 5, 6, and 7 were reported for the first time, and range from 1.08 to 12.92 μM. Based on the structure-activity relationship, the presence of hydroxyl, resorcinol, and prenyl moieties was important in the prevention of diabetes' pathological mechanisms, and these findings have been further supported by molecular docking analysis. These computational and experimental results will be useful in the development of therapeutic candidates to prevent/treat diabetes and its complications.

Sarikaphuti A, Nararatwanchai T, Hashiguchi T, Ito T, Thaworanunta S, Kikuchi K, Oyama Y, Maruyama I, Tancharoen S. Preventive effects of Morus alba L. anthocyanins on diabetes in Zucker diabetic fatty rats. Exp Ther Med. 2013 Sep;6(3):689-695. doi: 10.3892/etm.2013.1203. Epub 2013 Jul 4. PMID: 24137248; PMCID: PMC3786992.

Abstract. The mulberry plant (Morus alba L.) contains abundant anthocyanins (ANCs), which are natural antioxidants. The aim of this study was to determine the ANC composition of Thai Morus alba L. fruits and to assess the effect of an ANC extract on blood glucose and insulin levels in male leptin receptor-deficient Zucker diabetic fatty (ZDF) rats. The major components of the ANC extract were identified by high-performance liquid chromatography-electrospray ionization-mass spectrometry. ZDF and lean rats were treated with 125 or 250 mg ANCs/kg body weight, or 1% carboxymethylcellulose (CMC) twice daily for 5 weeks. Neither ANC dose had an effect on body weight. Following 5 weeks of treatment, glucose levels were observed to increase from 105.5±8.7 to 396.25±21 mg/dl (P<0.0001) in the CMC-treated ZDF rats; however, the glucose levels were significantly lower in the rats treated with 125 or 250 mg/kg ANCs (228.25±45 and 131.75±10 mg/dl, respectively; P<0.001 versus CMC). The administration of 250 mg/kg ANCs normalized glucose levels in the ZDF rats towards those of the lean littermates. Insulin levels were decreased significantly in the ZDF rats treated with CMC or 125 mg/kg ANCs (P<0.0001), but not in the rats treated with 250 mg/kg ANCs. Histologically, 250 mg/kg ANCs was observed to prevent islet degeneration compared with the islets in CMC-treated rats. This study, demonstrated that ANCs extracted from Morus alba L. were well tolerated and exhibited effective anti-diabetic properties in ZDF rats. ANCs represent a promising class of therapeutic compounds that may be useful in the prevention of type 2 diabetes.

Rodrigues EL, Marcelino G, Silva GT, Figueiredo PS, Garcez WS, Corsino J, Guimarães RCA, Freitas KC. Nutraceutical and Medicinal Potential of the Morus Species in Metabolic Dysfunctions. Int J Mol Sci. 2019 Jan 14;20(2):301. doi: 10.3390/ijms20020301.

Abstract. Many populations use medicinal plants as a therapeutic treatment, due to their lower cost and greater access. Among the plant species used for medicinal purposes are those of the genus Morus. The most known species are Morus alba, rubra, and nigra. This review aims to collect data from the literature, predominantly from cell and animal studies, which presents a possible nutraceutical and medicinal potential of the species Morus for use in metabolic dysfunctions. The fruits and leaves of mulberry are used for therapeutic purposes. For scientific confirmation of these effects, they were studied for laxative properties, antibacterial activity, anti-atherogenic activity, and hepatoprotective function. Furthermore, the genus Morus is recognized for the treatment and prevention of diabetes mellitus, through its hypoglycemic action. It may also provide health benefits through immunomodulatory, anti-inflammatory, and anti-nociceptive effects. It has been found that the Morus species have phenolic compounds, flavonoids, and anthocyanins that act as important antioxidants and promote beneficial effects on human health. These phytochemical compounds differ among species. Blackberry (Morus nigra) are rich in flavonoids, while the white mulberry (Morus alba) has low concentrations of flavonoids and anthocyanins. In addition, another important factor is to ensure a complete exemption of toxic risks in the use of medicinal plants for the treatment of diseases. Studies have shown no toxic effects by the administration of extracts of Morus species. Thus, the mulberry tree presents nutraceutical potential. It is therefore a promising alternative for medicinal products based on medicinal plants.