Lian Qiao (Forsythia Suspensa)
“Shen Nong’s Herbal Classic”
【Pinyin Name】Lián Qiáo
【Aliases】Hàn Lián Zǐ, Dà Qiáo Zǐ, Kōng Qiáo, Kōng Ké, Luò Qiáo
【Source】Medicinal Material: The fruit of the plant Forsythia suspensa, belonging to the Oleaceae family.
Latin Botanical Name: Forsythia suspensa (Thunb.) Vahl [Syringa suspensa Thunb.]
Harvesting and Storage: Lian Qiao flowers and fruits after 3-4 years of planting. Medicinally, it is categorized into “Qing Qiao” and “Lao Qiao”. Qing Qiao is harvested in early September when the fruit is still green and unripe, briefly boiled in hot water or steamed for about 0.5 hours, then dried. Lao Qiao is harvested in early October when the fruit is fully ripe and yellow, the fruit shell splits open, then dried and seeds and impurities are removed.
【Morphology】Deciduous shrub. The young branches are yellowish-brown or gray-brown, slightly four-angled, sparsely covered with lenticels, hollow between nodes, and solid pith at the nodes. Leaves are usually simple or trifoliate; petioles are 0.8-1.5 cm long, hairless; leaf blades are ovate, broad-ovate, or elliptical, 2-10 cm long and 1.5-5 cm wide, with a sharp tip and a rounded to wedge-shaped base, serrated margins except at the base. Flowers are usually solitary or in clusters of 2 to several in leaf axils, blooming before the leaves; pedicels are 5-6 mm long; calyx is green with 4 lobes, long oval or elongated oval, with fringed edges; corolla is yellow with 4 lobes, inverted oval, 1.2-2 cm long and 6-10 mm wide; there are 2 stamens at the base of the corolla tube; the style is slender with a bifid stigma. The capsule is ovoid, 2-celled, 1.2-2.5 cm long and 0.6-1.2 cm wide, with a beak-like tip and a surface with sparse tubercles; the peduncle is 0.7-1.5 cm long. Flowering occurs from March to April, and fruiting from July to September.
【Habitat Distribution】Ecological Environment: Grows in shrublands, sparse forests, and grasslands on hillsides.
Resource Distribution: Found in Hebei, Shanxi, Shaanxi, Gansu, Shandong, Jiangsu, Anhui, Henan, Hubei, Sichuan, and other regions. Currently cultivated.
【Cultivation】Biological Characteristics: Prefers warm and humid climates. Highly adaptable, cold-resistant, and drought-tolerant. Prefers full sunlight. Soil requirements are not strict, can grow in humus and sandy gravel soils.
【Characteristics】Identification: The fruit is elongated oval to oval, slightly flattened, 1-2.5 cm long, and 0.5-1.3 cm in diameter. “Lao Qiao” often splits from the tip, slightly curling outward or splitting into two lobes, with a fruit stalk or its scar at the base; the outer surface is yellow-brown with irregular longitudinal wrinkles and numerous pale yellow tubercles, fewer tubercles at the base, and a central longitudinal groove; the inner surface is pale yellow-brown, smooth, slightly glossy, with a central septum, and most seeds have fallen off, the fruit skin is hard and brittle, with a flat cross-section. “Qing Qiao” usually does not split, with a green-brown surface, fewer tubercles, often with a fruit stalk at the base, containing many seeds, lanceolate, slightly curved, about 0.7 cm long and 0.2 cm wide, brown on one side with a narrow wing. The aroma is faint, and the taste is bitter.
“Qing Qiao” is best when green and uncracked; “Lao Qiao” is best when yellow, with large lobes and thick shells.
Microscopic Identification: The transverse section of the fruit skin shows the outer pericarp consisting of a single row of tangentially elongated epidermal cells, covered with a cuticle, with thin-walled tissue protruding at the tubercles. The mesocarp consists of 10-30 rows of thin-walled cells, with varying wall thickness, containing pit pores, rarely containing square crystals; the outer fibrous vascular bundles vary in size, and stone cell clusters and fiber bundles are often found on the inner side of the woody part of Lao Qiao, sometimes seen in Qing Qiao. The inner pericarp consists of 5-14 rows of thick-walled tissue, arranged in a crisscross pattern, mostly consisting of lignified fiber bundles interspersed with stone cell clusters, with varying wall thickness. The innermost layer consists of a single row of smaller tangentially elongated inner epidermal cells.
Physicochemical Identification: (1) Take 1 g of the powdered product, add 10 ml of 70% ethanol for hot extraction, and evaporate the extract. Dissolve the residue in 1 ml of glacial acetic acid, then add 1 ml of sulfuric acid along the wall of a small test tube, a purple-red ring appears between the two liquid layers. (Check for triterpenoid saponins) (2) Take 0.5 g of the powdered product, add 5 ml of ether, shake for 5 minutes, filter, and place the filtrate in a small test tube, add 3 drops of 7% hydroxylamine hydrochloride methanol solution, and 3 drops of 20% potassium hydroxide methanol solution, heat in a water bath for 2 minutes, cool, add 1% hydrochloric acid to make it slightly acidic, then add 2 drops of 1% ferric chloride ethanol solution, resulting in a purple-red color. (Check for coumarin) (3) Thin-layer chromatography: Take 3 g of the powdered product, add 20 ml of water, decoct for 30 minutes, add 6 mol/L hydrochloric acid, adjust pH to 2, then extract with 20 ml of ether, recover the residue after ether extraction, and dissolve it in 0.5 ml of ethanol as the test solution. Prepare a control solution with oleanolic acid. Spot both solutions on the same silica gel H-1% CMC thin-layer plate, using chloroform-methanol (20:1) as the developing agent, develop, dry, spray with 10% sulfuric acid, and heat at 110°C for 10 minutes. The test solution should show the same gray-black spots at the corresponding positions as the control solution. Alternatively, after iodine fuming, the same yellow-brown spots should appear.
【Processing】Remove impurities, rub open, and remove branches and stems.
【Properties and Flavor】Bitter; slightly cold in nature.
【Meridian Affinity】Lung; Heart; Gallbladder meridians.
【Functions and Indications】Clears heat and detoxifies; reduces swelling and disperses nodules. Indicated for wind-heat colds. Main indications include wind-heat colds; warm diseases; heat stranguria; carbuncles; swelling and toxicity; scrofula; goiter; throat obstruction.
【Dosage】Internal use: decoction, 6-15 g; or in pills or powders.
【Precautions】1. Avoid use in cases of spleen and stomach deficiency, qi deficiency with fever, and carbuncles that have already suppurated with pale pus.
2. According to “Bencao Jing Shu”: do not use in cases of carbuncles that have already suppurated, high fever due to deficiency, and those with weak spleen and stomach prone to diarrhea.
【Pharmacological Effects】1. Antibacterial and antiviral effects: 1.1. Antibacterial effects: The volatile oil emulsion of Lian Qiao seeds was tested for antibacterial activity using a dilution method in test tubes. The results showed that this herb had strong antibacterial effects against 10 strains of Gram-positive and Gram-negative bacteria, except for a slightly lower effect on Pseudomonas aeruginosa. The strongest effect was against Staphylococcus aureus (antibacterial efficacy of 1/1.024); followed by Streptococcus pneumoniae; Group A and B streptococci; Enterobacter cloacae; Shigella dysenteriae; Salmonella paratyphi A; (antibacterial efficacy of 1/512) and Escherichia coli (antibacterial efficacy of 1/256). The antibacterial efficacy against Klebsiella pneumoniae and Proteus vulgaris was 1/28. The selected test liquid with antibacterial activity underwent subculture tests, showing that the volatile oil of Lian Qiao seeds had thorough and stable antibacterial effects. The concentrated decoction of Lian Qiao has antibacterial effects in vitro, inhibiting Salmonella, Shigella, E. coli, diphtheria bacillus, cholera vibrio, Staphylococcus, and Streptococcus. The antibacterial action of Lian Qiao in vitro is similar to that of Jin Yin Hua (Honeysuckle); it is a major antibacterial component in Yin Qiao San. Jin Yin Hua has a stronger inhibitory effect on Salmonella, especially typhoid bacillus and hemolytic streptococcus, while Lian Qiao shows better inhibition against Shigella and Staphylococcus aureus. When used together, there is no synergistic effect in vitro, and the combination with Huang Lian and Huang Qin shows stronger antibacterial effects than using Lian Qiao alone. Research on the effective antibacterial components in Lian Qiao is limited; Lian Qiao phenol showed an antibacterial concentration of 1:5120 against Staphylococcus aureus; 1:1280 against Shigella; and 1:640 against diphtheria bacillus and paratyphoid (A) bacillus, which may be the effective antibacterial components. The flowers have certain efficacy against experimental tuberculosis in mice but are ineffective in guinea pigs. Additionally, its anti-tuberculosis effects have been reported in vitro and clinically. The alcohol extract of Lian Qiao has some inhibitory effects against Leptospira, though not as strong as Huang Lian, Lychee grass, or Jin Yin Hua, Huang Qin, but similar to Huang Bai and Zao Jiao. The water extract of Lian Qiao (1:5) has some inhibitory effects against Nocardia asteroides.
1.2. Antifungal effects: The volatile oil emulsion of Lian Qiao seeds was tested against Candida albicans and tropical Candida, showing significant antifungal activity with efficacy values of 1/1.024 and 1/512, respectively.
1.3. Antiviral effects: The volatile oil emulsion of Lian Qiao seeds was tested for antiviral activity against Asian influenza virus and type I parainfluenza virus using chicken embryos (drug concentration of 1/32). It showed significant antiviral effects against both viruses when administered simultaneously with infection. The antiviral efficacy against both tested viruses was 1/65,536. Using dot hybridization, Lian Qiao decoction at concentrations of 25%-100% reduced the content of hepatitis B virus DNA (HBVDNA).
2. Effects on the cardiovascular system: 2.1. The effects of Lian Qiao injection on the heart of cats during toxic shock: In an experiment with 3 cats under abdominal anesthesia, carotid artery cannulation was performed to measure blood pressure, and tracheal intubation was done for mechanical ventilation. The chest and pericardium were opened to expose the heart, and the heart contraction curve was recorded. After establishing a normal control, a dose of 0.8-2.5 ml/kg of typhoid vaccine was injected intravenously, resulting in significant myocardial damage (irregular myocardial contraction waves and decreased blood pressure). After intravenous injection of Lian Qiao injection at 8 g/kg, the heart rhythm normalized, and in 2 cats, the amplitude of myocardial contraction waves increased, with blood pressure rising by about 40 mmHg after 30 minutes, indicating a positive inotropic and pressor effect.
2.2. Effects on capillary permeability: Healthy mice (both sexes, weighing 18-22 g) were divided into experimental and control groups. The experimental group (7 animals) received Lian Qiao injection (60 g/kg) via tail vein or subcutaneous injection, while the control group (9 animals) received physiological saline (0.4 ml/animal). After 10 minutes, 0.5% Evans blue solution (0.2 ml/animal) was injected via the tail vein. After 30 minutes, 0.4% acetic acid (0.4 ml/animal) was injected intraperitoneally. After another 30 minutes, the mice were sacrificed, and the peritoneal exudate was washed with physiological saline, and the exudate was measured for Evans blue concentration. The results showed that the Evans blue concentration in the control group was 368.47±28.55 (mean ± standard deviation), while in the experimental group it was 160.12±28.37 (P<0.01), indicating that Lian Qiao injection significantly inhibited capillary permeability induced by acetic acid.
3. Inhibitory effects on isolated small intestine: Experiments were conducted on guinea pigs using the Magnur method for isolated intestinal specimens. The isolated small intestine was placed in Lian Qiao nutrient solution (12×10-2), with 10 trials conducted. Results showed reduced intestinal tension in 4 trials, and 6 trials showed an initial increase followed by a decrease. The contraction amplitude decreased in 8 trials, with no change in 2 trials. Physiological saline had no effect on the isolated intestine, indicating that Lian Qiao has an inhibitory effect on the isolated small intestine of guinea pigs.
4. Inhibition of elastase activity: Lian Qiao was diluted to concentrations of 1.5 g/ml, 0.75 g/ml, and 0.375 g/ml. Porcine pancreatic elastase (PPE) was diluted to 19 u/0.5 mg·ml and 9.5 u/0.25 mg·ml. The enzyme solution was mixed with the different concentrations of Lian Qiao, and after incubation at 37°C for 24 hours, the diameter of the lysis ring was measured. The results showed that all three concentrations of Lian Qiao significantly inhibited the elastase activity (P<0.001), with complete inhibition at a concentration of 7.5 mg. The water-soluble crude extract of Lian Qiao at 10-3 g/ml and 10-4 g/ml also inhibited phospholipase activity.
5. Radioprotective effects: The methanol extract of Lian Qiao at 1 g/kg administered intraperitoneally 5 minutes before X-ray exposure showed protective effects against skin damage in mice.
【Toxicity】The LD50 of Lian Qiao injection (1:1) in mice via intraperitoneal injection is 24.85±1.12 g/kg. The LD50 of compound Lian Qiao injection in mice via intraperitoneal injection is 119.5 g (raw herb)/kg.