The Rutaceae family, also known as the rue or citrus family, is a large group of plants in the order Sapindales, consisting of about 160 genera and over 1,600 species. This family includes a diverse range of plants, from small shrubs and herbaceous plants to large trees, many of which are aromatic and have important culinary, medicinal, and industrial uses. It is best known for its inclusion of citrus fruits, which are globally important in the food industry.

General Description

Plants in the Rutaceae family are typically characterized by:

• Leaves: Usually aromatic, simple, and alternately arranged. They often contain oil glands that produce essential oils, giving them a characteristic fragrance.
• Flowers: The flowers are often showy, with five petals and numerous stamens. They are typically fragrant and may be solitary or in clusters, attracting pollinators such as bees and butterflies.
• Fruits: The fruits of the Rutaceae family vary widely, but many species produce berry-like fruits, including the well-known citrus fruits. Some fruits, like those of the citrus genus (Citrus), are edible and consumed worldwide.

Many species of Rutaceae are important for the production of essential oils, fruits, and have applications in both traditional and modern medicine.

Chemical Composition

The Rutaceae family is rich in bioactive compounds, particularly essential oils. Some notable compounds include:

• Essential oils: The most famous oils from this family include those from citrus fruits (Citrus), bergamot (Citrus bergamia), and rue (Ruta graveolens). These oils contain compounds like limonene, citral, and linalool, which are known for their refreshing, anti-inflammatory, and antimicrobial properties.
• Flavonoids: These compounds are present in many species of Rutaceae and are known for their antioxidant, anti-inflammatory, and anticancer properties.
• Alkaloids: Some species, particularly Ruta graveolens (rue), contain alkaloids that have medicinal applications, although they can be toxic in high doses.
• Coumarins: Found in some members of the family, these compounds have anticoagulant and antimicrobial properties.

These compounds make Rutaceae species valuable in the production of essential oils, perfumes, and medicines.

Physical Properties

The plants in the Rutaceae family generally have the following characteristics:

• Leaves: Often aromatic due to oil glands that secrete essential oils. The leaves may also be leathery or glossy, which helps prevent water loss.
• Flowers: Typically showy, with five petals and many stamens. The flowers often have a strong, pleasant fragrance that attracts pollinators.
• Fruits: Many species produce fleshy fruits, including citrus fruits, which are either sour or sweet. The fruit typically contains multiple seeds.
• Roots and Stems: The family includes woody species such as trees and shrubs, as well as herbaceous plants. The stems of some species produce aromatic oils.

The ability to produce aromatic oils is one of the defining features of this family, making many of its members significant in the fragrance and essential oil industries.

Production Process

Plants in the Rutaceae family are primarily propagated by seed, although some species can also be propagated by cuttings or grafting, particularly in the case of cultivated citrus plants. For citrus fruits, seeds are sown and trees are grown in orchards, while for essential oil production, the flowers, leaves, or peel are harvested and processed through distillation.

In the case of citrus, the fruits are harvested and processed for consumption, juice extraction, or zest production, while essential oils are extracted from the peel through cold pressing or steam distillation.

Applications

Medicinal

Many plants in the Rutaceae family have medicinal properties:

• Citrus fruits (Citrus spp.): Rich in vitamin C, citrus fruits are known for their immune-boosting and antioxidant properties. They also have anti-inflammatory and antimicrobial effects.
• Bergamot (Citrus bergamia): The essential oil of bergamot is used in aromatherapy for its calming and mood-lifting properties.
• Rue (Ruta graveolens): Traditionally used for its antimicrobial, anti-inflammatory, and digestive properties. It has been used in folk medicine for conditions like indigestion, arthritis, and menstrual problems.
• Grapefruit (Citrus paradisi): Contains compounds that can aid in digestion, help detoxify the body, and improve circulation.

Cosmetic

The Rutaceae family is widely known for the production of essential oils, which are used in the cosmetic industry for their fragrance and therapeutic properties:

• Citrus oils: Essential oils from fruits like oranges, lemons, and limes are used in skincare products for their refreshing and purifying properties. They are also used for their antioxidant and antimicrobial effects.
• Bergamot oil: Used in perfumes and skincare products for its calming properties, often added to products designed to reduce stress or promote relaxation.
• Grapefruit oil: Known for its revitalizing properties, it is used in body care products to improve skin tone and texture.

Environmental

Members of the Rutaceae family, such as citrus trees, play important roles in agriculture, particularly in the production of fruits like oranges, lemons, and grapefruits. Additionally, citrus trees are used in agroforestry to enhance soil quality, provide shade, and support biodiversity.

Culinary

The fruits of the Rutaceae family, particularly the citrus species, are some of the most widely consumed fruits in the world. These fruits are enjoyed fresh, juiced, or used in cooking, baking, and making beverages. Citrus zest is also a common ingredient in culinary applications, providing a burst of citrus flavor.

Environmental and Safety Considerations

While many species in the Rutaceae family are safe for medicinal, culinary, and cosmetic use, some species can be toxic if consumed improperly or in large quantities. For example:

• Rue (Ruta graveolens): Rue contains compounds that can be toxic in large doses and should be used with caution. It can also cause skin irritation in some individuals.
• Citrus oils: While generally safe, some citrus oils (like lemon and lime) can increase photosensitivity, making the skin more prone to sunburn.

When using essential oils from Rutaceae, it is important to dilute them properly and follow recommended guidelines to avoid irritation or adverse reactions.

INCI Functions

• Antioxidant: Protects the skin from oxidative stress.
• Anti-inflammatory: Reduces skin inflammation and redness.
• Antimicrobial: Fights harmful microorganisms on the skin.
• Moisturizing: Helps maintain skin hydration.

Conclusion

The Rutaceae family is a significant and diverse group of plants with numerous applications across many industries, including food, medicine, cosmetics, and environmental management. From citrus fruits to fragrant essential oils, the family has contributed substantially to human health, agriculture, and culture. With proper care and knowledge, plants in this family offer a wide range of benefits, from boosting immunity to providing refreshing scents in cosmetic products.

References__________________________________________________________________________
Aliberti L, Caputo L, De Feo V, De Martino L, Nazzaro F, Souza LF. Chemical Composition and in Vitro Antimicrobial, Cytotoxic, and Central Nervous System Activities of the Essential Oils of Citrus medica L. cv. 'Liscia' and C. medica cv. 'Rugosa' Cultivated in Southern Italy. Molecules. 2016 Sep 18;21(9):1244. doi: 10.3390/molecules21091244.

Abstract. Citrus medica cv. 'liscia' and C. medica cv. 'rugosa' are two taxa of citron, belonging to the biodiversity of South Italy, in particular of Amalfi Coast, in the Campania region. The chemical composition of the essential oils (EOs) from fruit peels of both C. medica cultivars was studied by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analyses. In all, 100 compounds were identified, 82 for C. medica cv. 'liscia', accounting for 91.4% of the total oil, and 88 for C. medica cv. 'rugosa', accounting for 92.0% of the total oil. Monoterpene hydrocarbons are the main constituents in both oils of C. medica cv. 'liscia' (79.1%) and C. medica cv. 'rugosa' (80.2%). In both oils, limonene (67.2%-62.8%) and camphene (8.5%-10.9%) are the main constituents. The antimicrobial activity of the EOs was assayed against some bacterial strains: Bacillus cereus (DSM 4313), Bacillus cereus (DSM 4384), Staphylococcus aureus (DSM 25693), Pseudomonas aeruginosa (ATCC 50071), and Escherichia coli (DSM 8579). Low concentrations of C. medica cv. 'rugosa' EO showed an inhibitory effect on P. aeruginosa and higher concentrations inhibited more B. cereus (4384) and E. coli than S. aureus. The cytotoxicity of the EO was evaluated against SH-SY5Y cell line. The influence of the EO on the expression of adenylate cyclase 1 (ADCY1) was also studied. The antimicrobial activity registered confirm their traditional uses as food preserving agents and led us to hypothesize the possible use of these oils as antimicrobials. The alterations in ADCY1 expression suggested a role for limonene in effects on the central nervous system.

Ledesma-Escobar CA, Priego-Capote F, Luque de Castro MD. Comparative Study of the Effect of Sample Pretreatment and Extraction on the Determination of Flavonoids from Lemon (Citrus limon). PLoS One. 2016 Jan 25;11(1):e0148056. doi: 10.1371/journal.pone.0148056.

 Abstract. Background: Flavonoids have shown to exert multiple beneficial effects on human health, being also appreciated by both food and pharmaceutical industries. Citrus fruits are a key source of flavonoids, thus promoting studies to obtain them. Characteristics of these studies are the discrepancies among sample pretreatments and among extraction methods, and also the scant number of comparative studies developed so far. Objective: Evaluate the effect of both the sample pretreatment and the extraction method on the profile of flavonoids isolated from lemon.Results: Extracts from fresh, lyophilized and air-dried samples obtained by shaking extraction (SE), ultrasound-assisted extraction (USAE), microwave-assisted extraction (MAE) and superheated liquid extraction (SHLE) were analyzed by LC-QTOF MS/MS, and 32 flavonoids were tentatively identified using MS/MS information. ANOVA applied to the data from fresh and dehydrated samples and from extraction by the different methods revealed that 26 and 32 flavonoids, respectively, were significant (p≤0.01). The pairwise comparison (Tukey HSD; p≤0.01) showed that lyophilized samples are more different from fresh samples than from air-dried samples; also, principal component analysis (PCA) showed a clear discrimination among sample pretreatment strategies and suggested that such differences are mainly created by the abundance of major flavonoids. On the other hand, pairwise comparison of extraction methods revealed that USAE and MAE provided quite similar extracts, being SHLE extracts different from the other two. In this case, PCA showed a clear discrimination among extraction methods, and their position in the scores plot suggests a lower abundance of flavonoids in the extracts from SHLE. In the two PCA the loadings plots revealed a trend to forming groups according to flavonoid aglycones. Conclusions: The present study shows clear discrimination caused by both sample pretreatments and extraction methods. Under the studied conditions, liophilization provides extracts with higher amounts of flavonoids, and USAE is the best method for isolation of these compounds, followed by MAE and SE. On the contrary, the SHLE method was the less favorable to extract flavonoids from citrus owing to degradation.